21222978180 has 48 divisors (see below), whose sum is σ = 59514350784. Its totient is φ = 5650888320.

The previous prime is 21222978173. The next prime is 21222978221. The reversal of 21222978180 is 8187922212.

It is a super-2 number, since 2×21222978180² (a number of 21 digits) contains 22 as substring.

It is a hoax number, since the sum of its digits (42) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 227902 + ... + 307221.

It is an arithmetic number, because the mean of its divisors is an integer number (1239882308).

Almost surely, 2^21222978180 is an apocalyptic number.

21222978180 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21222978180 is an abundant number, since it is smaller than the sum of its proper divisors (38291372604).

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

21222978180 is a wasteful number, since it uses less digits than its factorization.

21222978180 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 535796 (or 535794 counting only the distinct ones).

The product of its (nonzero) digits is 64512, while the sum is 42.

The spelling of 21222978180 in words is "twenty-one billion, two hundred twenty-two million, nine hundred seventy-eight thousand, one hundred eighty".