20403125261 has 4 divisors (see below), whose sum is σ = 21061290624. Its totient is φ = 19744959900.

The previous prime is 20403125257. The next prime is 20403125287. The reversal of 20403125261 is 16252130402.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 16252130402 = 2 ⋅8126065201.

It is a cyclic number.

It is not a de Polignac number, because 20403125261 - 2² = 20403125257 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 20403125261.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20403125201) 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, 329082635 + ... + 329082696.

It is an arithmetic number, because the mean of its divisors is an integer number (5265322656).

Almost surely, 2^20403125261 is an apocalyptic number.

It is an amenable number.

20403125261 is a deficient number, since it is larger than the sum of its proper divisors (658165363).

20403125261 is an equidigital number, since it uses as much as digits as its factorization.

20403125261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 658165362.

The product of its (nonzero) digits is 2880, while the sum is 26.

Adding to 20403125261 its reverse (16252130402), we get a palindrome (36655255663).

The spelling of 20403125261 in words is "twenty billion, four hundred three million, one hundred twenty-five thousand, two hundred sixty-one".