25661530690 has 16 divisors (see below), whose sum is σ = 46195870392. Its totient is φ = 10263475584.

The previous prime is 25661530649. The next prime is 25661530693. The reversal of 25661530690 is 9603516652.

It can be written as a sum of positive squares in 4 ways, for example, as 25549784649 + 111746041 = 159843^2 + 10571^2 .

It is a super-2 number, since 2×25661530690² (a number of 22 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (25661530693) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 44049 + ... + 230788.

Almost surely, 2^25661530690 is an apocalyptic number.

25661530690 is a deficient number, since it is larger than the sum of its proper divisors (20534339702).

25661530690 is a wasteful number, since it uses less digits than its factorization.

25661530690 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 284181.

The product of its (nonzero) digits is 291600, while the sum is 43.

The spelling of 25661530690 in words is "twenty-five billion, six hundred sixty-one million, five hundred thirty thousand, six hundred ninety".