21011110164 has 72 divisors (see below), whose sum is σ = 58452593472. Its totient is φ = 6310644480.

The previous prime is 21011110111. The next prime is 21011110181. The reversal of 21011110164 is 46101111012.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 190024 + ... + 279519.

It is an arithmetic number, because the mean of its divisors is an integer number (811841576).

Almost surely, 2^21011110164 is an apocalyptic number.

It is an amenable number.

21011110164 is an abundant number, since it is smaller than the sum of its proper divisors (37441483308).

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

21011110164 is a wasteful number, since it uses less digits than its factorization.

21011110164 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 469677 (or 469672 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 18.

Adding to 21011110164 its reverse (46101111012), we get a palindrome (67112221176).

The spelling of 21011110164 in words is "twenty-one billion, eleven million, one hundred ten thousand, one hundred sixty-four".