25775587021 has 4 divisors (see below), whose sum is σ = 25886212092. Its totient is φ = 25664961952.

The previous prime is 25775586959. The next prime is 25775587099. The reversal of 25775587021 is 12078557752.

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 11233880100 + 14541706921 = 105990^2 + 120589^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-25775587021 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25775587921) 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, 55312186 + ... + 55312651.

It is an arithmetic number, because the mean of its divisors is an integer number (6471553023).

Almost surely, 2^25775587021 is an apocalyptic number.

It is an amenable number.

25775587021 is a deficient number, since it is larger than the sum of its proper divisors (110625071).

25775587021 is a wasteful number, since it uses less digits than its factorization.

25775587021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 110625070.

The product of its (nonzero) digits is 1372000, while the sum is 49.

The spelling of 25775587021 in words is "twenty-five billion, seven hundred seventy-five million, five hundred eighty-seven thousand, twenty-one".