21122120664 has 48 divisors (see below), whose sum is σ = 57929882400. Its totient is φ = 6951582144.

The previous prime is 21122120627. The next prime is 21122120671. The reversal of 21122120664 is 46602122112.

It is a super-2 number, since 2×21122120664² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1851039 + ... + 1862414.

It is an arithmetic number, because the mean of its divisors is an integer number (1206872550).

Almost surely, 2^21122120664 is an apocalyptic number.

21122120664 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21122120664 is an abundant number, since it is smaller than the sum of its proper divisors (36807761736).

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

21122120664 is a wasteful number, since it uses less digits than its factorization.

21122120664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3713544 (or 3713537 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 27.

Adding to 21122120664 its reverse (46602122112), we get a palindrome (67724242776).

The spelling of 21122120664 in words is "twenty-one billion, one hundred twenty-two million, one hundred twenty thousand, six hundred sixty-four".