25556587765 has 4 divisors (see below), whose sum is σ = 30667905324. Its totient is φ = 20445270208.

The previous prime is 25556587751. The next prime is 25556587787. The reversal of 25556587765 is 56778565552.

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 5809031089 + 19747556676 = 76217^2 + 140526^2 .

It is a cyclic number.

It is not a de Polignac number, because 25556587765 - 2²⁷ = 25422370037 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2555658772 + ... + 2555658781.

It is an arithmetic number, because the mean of its divisors is an integer number (7666976331).

Almost surely, 2^25556587765 is an apocalyptic number.

It is an amenable number.

25556587765 is a deficient number, since it is larger than the sum of its proper divisors (5111317559).

25556587765 is an equidigital number, since it uses as much as digits as its factorization.

25556587765 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5111317558.

The product of its digits is 88200000, while the sum is 61.

The spelling of 25556587765 in words is "twenty-five billion, five hundred fifty-six million, five hundred eighty-seven thousand, seven hundred sixty-five".