25643617965 has 24 divisors (see below), whose sum is σ = 50798786688. Its totient is φ = 11722796640.

The previous prime is 25643617963. The next prime is 25643617969. The reversal of 25643617965 is 56971634652.

25643617965 is a `hidden beast` number, since 2 + 564 + 3 + 6 + 1 + 79 + 6 + 5 = 666.

It is not a de Polignac number, because 25643617965 - 2¹ = 25643617963 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25643617963) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 40703841 + ... + 40704470.

It is an arithmetic number, because the mean of its divisors is an integer number (2116616112).

Almost surely, 2^25643617965 is an apocalyptic number.

It is an amenable number.

25643617965 is a deficient number, since it is larger than the sum of its proper divisors (25155168723).

25643617965 is a wasteful number, since it uses less digits than its factorization.

25643617965 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81408329 (or 81408326 counting only the distinct ones).

The product of its digits is 8164800, while the sum is 54.

The spelling of 25643617965 in words is "twenty-five billion, six hundred forty-three million, six hundred seventeen thousand, nine hundred sixty-five".