21255425156516 has 6 divisors (see below), whose sum is σ = 37196994023910. Its totient is φ = 10627712578256.

The previous prime is 21255425156503. The next prime is 21255425156557. The reversal of 21255425156516 is 61565152455212.

It can be written as a sum of positive squares in only one way, i.e., 19696323306916 + 1559101849600 = 4438054^2 + 1248640^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2656928144561 + ... + 2656928144568.

It is an arithmetic number, because the mean of its divisors is an integer number (6199499003985).

Almost surely, 2^{21255425156516} is an apocalyptic number.

It is an amenable number.

21255425156516 is a deficient number, since it is larger than the sum of its proper divisors (15941568867394).

21255425156516 is a wasteful number, since it uses less digits than its factorization.

21255425156516 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5313856289133 (or 5313856289131 counting only the distinct ones).

The product of its digits is 3600000, while the sum is 50.

The spelling of 21255425156516 in words is "twenty-one trillion, two hundred fifty-five billion, four hundred twenty-five million, one hundred fifty-six thousand, five hundred sixteen".