21355525056464 has 20 divisors (see below), whose sum is σ = 41874839797056. Its totient is φ = 10549114786272.

The previous prime is 21355525056389. The next prime is 21355525056497. The reversal of 21355525056464 is 46465052555312.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8040482504 + ... + 8040485159.

Almost surely, 2^{21355525056464} is an apocalyptic number.

It is an amenable number.

21355525056464 is a deficient number, since it is larger than the sum of its proper divisors (20519314740592).

21355525056464 is a wasteful number, since it uses less digits than its factorization.

21355525056464 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16080967754 (or 16080967748 counting only the distinct ones).

The product of its (nonzero) digits is 21600000, while the sum is 53.

The spelling of 21355525056464 in words is "twenty-one trillion, three hundred fifty-five billion, five hundred twenty-five million, fifty-six thousand, four hundred sixty-four".