25787748813561 has 48 divisors (see below), whose sum is σ = 44065703410560. Its totient is φ = 14218835097600.

The previous prime is 25787748813559. The next prime is 25787748813569. The reversal of 25787748813561 is 16531884778752.

25787748813561 is a `hidden beast` number, since 2 + 5 + 7 + 8 + 7 + 7 + 48 + 8 + 13 + 561 = 666.

It is not a de Polignac number, because 25787748813561 - 2¹ = 25787748813559 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 25787748813561.

It is not an unprimeable number, because it can be changed into a prime (25787748813569) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1483095 + ... + 7333148.

It is an arithmetic number, because the mean of its divisors is an integer number (918035487720).

Almost surely, 2^{25787748813561} is an apocalyptic number.

25787748813561 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

25787748813561 is a deficient number, since it is larger than the sum of its proper divisors (18277954596999).

25787748813561 is a wasteful number, since it uses less digits than its factorization.

25787748813561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8817886 (or 8817883 counting only the distinct ones).

The product of its digits is 632217600, while the sum is 72.

The spelling of 25787748813561 in words is "twenty-five trillion, seven hundred eighty-seven billion, seven hundred forty-eight million, eight hundred thirteen thousand, five hundred sixty-one".