25511721215640 has 64 divisors (see below), whose sum is σ = 83492905800960. Its totient is φ = 6184659688320.

The previous prime is 25511721215611. The next prime is 25511721215647. The reversal of 25511721215640 is 4651212711552.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 25511721215592 and 25511721215601.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25511721215647) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9663529444 + ... + 9663532083.

It is an arithmetic number, because the mean of its divisors is an integer number (1304576653140).

Almost surely, 2^{25511721215640} is an apocalyptic number.

25511721215640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

25511721215640 is an abundant number, since it is smaller than the sum of its proper divisors (57981184585320).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

25511721215640 is a wasteful number, since it uses less digits than its factorization.

25511721215640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19327061552 (or 19327061548 counting only the distinct ones).

The product of its (nonzero) digits is 168000, while the sum is 42.

The spelling of 25511721215640 in words is "twenty-five trillion, five hundred eleven billion, seven hundred twenty-one million, two hundred fifteen thousand, six hundred forty".