203671000261 has 4 divisors (see below), whose sum is σ = 203671957612. Its totient is φ = 203670042912.

The previous prime is 203671000229. The next prime is 203671000321. The reversal of 203671000261 is 162000176302.

203671000261 is a nontrivial binomial coefficient, being equal to C(638234, 2).

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 162000176302 = 2 ⋅81000088151.

It can be written as a sum of positive squares in 2 ways, for example, as 26624448900 + 177046551361 = 163170^2 + 420769^2 .

It is a 3-Lehmer number, since φ(203671000261) divides (203671000261-1)³.

It is a cyclic number.

It is not a de Polignac number, because 203671000261 - 2⁵ = 203671000229 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (203671010261) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1 + ... + 638233.

It is an arithmetic number, because the mean of its divisors is an integer number (50917989403).

It is a Poulet number, since it divides 2^203671000260-1.

Almost surely, 2^203671000261 is an apocalyptic number.

203671000261 is the 638233-rd triangular number and also the 319117-th hexagonal number.

203671000261 is the 212745-th centered nonagonal number.

It is an amenable number.

203671000261 is a deficient number, since it is larger than the sum of its proper divisors (957351).

203671000261 is an equidigital number, since it uses as much as digits as its factorization.

203671000261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 957350.

The product of its (nonzero) digits is 3024, while the sum is 28.

Adding to 203671000261 its reverse (162000176302), we get a palindrome (365671176563).

The spelling of 203671000261 in words is "two hundred three billion, six hundred seventy-one million, two hundred sixty-one", and thus it is an aban number.