21221522260164 has 48 divisors (see below), whose sum is σ = 55076859633600. Its totient is φ = 7066370982528.

The previous prime is 21221522260157. The next prime is 21221522260189. The reversal of 21221522260164 is 46106222512212.

21221522260164 is a `hidden beast` number, since 2 + 1 + 2 + 21 + 5 + 2 + 22 + 601 + 6 + 4 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 103644069 + ... + 103848620.

It is an arithmetic number, because the mean of its divisors is an integer number (1147434575700).

Almost surely, 2^{21221522260164} is an apocalyptic number.

It is an amenable number.

21221522260164 is an abundant number, since it is smaller than the sum of its proper divisors (33855337373436).

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

21221522260164 is a wasteful number, since it uses less digits than its factorization.

21221522260164 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 207493649 (or 207493641 counting only the distinct ones).

The product of its (nonzero) digits is 46080, while the sum is 36.

Adding to 21221522260164 its reverse (46106222512212), we get a palindrome (67327744772376).

The spelling of 21221522260164 in words is "twenty-one trillion, two hundred twenty-one billion, five hundred twenty-two million, two hundred sixty thousand, one hundred sixty-four".