21864822012 has 72 divisors (see below), whose sum is σ = 60313274112. Its totient is φ = 6623575200.

The previous prime is 21864821999. The next prime is 21864822037. The reversal of 21864822012 is 21022846812.

21864822012 is a `hidden beast` number, since 2 + 1 + 8 + 648 + 2 + 2 + 0 + 1 + 2 = 666.

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

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, 1587837 + ... + 1601547.

Almost surely, 2^21864822012 is an apocalyptic number.

21864822012 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21864822012 is an abundant number, since it is smaller than the sum of its proper divisors (38448452100).

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

21864822012 is a wasteful number, since it uses less digits than its factorization.

21864822012 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17759 (or 17754 counting only the distinct ones).

The product of its (nonzero) digits is 24576, while the sum is 36.

The spelling of 21864822012 in words is "twenty-one billion, eight hundred sixty-four million, eight hundred twenty-two thousand, twelve".