21152516222664 has 24 divisors (see below), whose sum is σ = 57288064769910. Its totient is φ = 7050838740864.

The previous prime is 21152516222639. The next prime is 21152516222687. The reversal of 21152516222664 is 46622261525112.

21152516222664 is a `hidden beast` number, since 2 + 1 + 1 + 52 + 516 + 2 + 2 + 26 + 64 = 666.

It can be written as a sum of positive squares in only one way, i.e., 19020501562500 + 2132014660164 = 4361250^2 + 1460142^2 .

It is a tau number, because it is divible by the number of its divisors (24).

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 146892473697 + ... + 146892473840.

Almost surely, 2^{21152516222664} is an apocalyptic number.

21152516222664 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21152516222664 is an abundant number, since it is smaller than the sum of its proper divisors (36135548547246).

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

21152516222664 is a wasteful number, since it uses less digits than its factorization.

21152516222664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 293784947549 (or 293784947542 counting only the distinct ones).

The product of its digits is 691200, while the sum is 45.

Adding to 21152516222664 its reverse (46622261525112), we get a palindrome (67774777747776).

The spelling of 21152516222664 in words is "twenty-one trillion, one hundred fifty-two billion, five hundred sixteen million, two hundred twenty-two thousand, six hundred sixty-four".