21164206120056 has 64 divisors (see below), whose sum is σ = 58790225779200. Its totient is φ = 7054643653344.

The previous prime is 21164206120051. The next prime is 21164206120067. The reversal of 21164206120056 is 65002160246112.

21164206120056 is a `hidden beast` number, since 2 + 1 + 1 + 642 + 0 + 6 + 1 + 2 + 0 + 0 + 5 + 6 = 666.

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

It is a self number, because there is not a number n which added to its sum of digits gives 21164206120056.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21164206120051) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 17164335 + ... + 18356001.

It is an arithmetic number, because the mean of its divisors is an integer number (918597277800).

Almost surely, 2^{21164206120056} is an apocalyptic number.

It is an amenable number.

21164206120056 is an abundant number, since it is smaller than the sum of its proper divisors (37626019659144).

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

21164206120056 is a wasteful number, since it uses less digits than its factorization.

21164206120056 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1273905 (or 1273895 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 36.

Adding to 21164206120056 its reverse (65002160246112), we get a palindrome (86166366366168).

The spelling of 21164206120056 in words is "twenty-one trillion, one hundred sixty-four billion, two hundred six million, one hundred twenty thousand, fifty-six".