261903421 has 4 divisors (see below), whose sum is σ = 282049852. Its totient is φ = 241756992.

The previous prime is 261903401. The next prime is 261903431. The reversal of 261903421 is 124309162.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 140683321 + 121220100 = 11861^2 + 11010^2 .

It is a cyclic number.

It is not a de Polignac number, because 261903421 - 2¹³ = 261895229 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 261903421.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261903401) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10073196 + ... + 10073221.

It is an arithmetic number, because the mean of its divisors is an integer number (70512463).

Almost surely, 2^261903421 is an apocalyptic number.

It is an amenable number.

261903421 is a deficient number, since it is larger than the sum of its proper divisors (20146431).

261903421 is a wasteful number, since it uses less digits than its factorization.

261903421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20146430.

The product of its (nonzero) digits is 2592, while the sum is 28.

The square root of 261903421 is about 16183.4304459839. The cubic root of 261903421 is about 639.8041563855.

The spelling of 261903421 in words is "two hundred sixty-one million, nine hundred three thousand, four hundred twenty-one".