25400615661 has 16 divisors (see below), whose sum is σ = 37636459200. Its totient is φ = 16931080944.

The previous prime is 25400615659. The next prime is 25400615687. The reversal of 25400615661 is 16651600452.

25400615661 is a `hidden beast` number, since 2 + 540 + 0 + 6 + 1 + 56 + 61 = 666.

It is not a de Polignac number, because 25400615661 - 2¹ = 25400615659 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25400615621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 109155 + ... + 250431.

It is an arithmetic number, because the mean of its divisors is an integer number (2352278700).

Almost surely, 2^25400615661 is an apocalyptic number.

It is an amenable number.

25400615661 is a deficient number, since it is larger than the sum of its proper divisors (12235843539).

25400615661 is a wasteful number, since it uses less digits than its factorization.

25400615661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 147945 (or 147939 counting only the distinct ones).

The product of its (nonzero) digits is 43200, while the sum is 36.

The spelling of 25400615661 in words is "twenty-five billion, four hundred million, six hundred fifteen thousand, six hundred sixty-one".