21012111221220 has 144 divisors (see below), whose sum is σ = 73510261144320. Its totient is φ = 4758706153728.

The previous prime is 21012111221207. The next prime is 21012111221249. The reversal of 21012111221220 is 2212211121012.

21012111221220 is a `hidden beast` number, since 2 + 10 + 1 + 211 + 1 + 221 + 220 = 666.

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

It is a junction number, because it is equal to n+sod(n) for n = 21012111221193 and 21012111221202.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 76359352 + ... + 76634031.

Almost surely, 2^{21012111221220} is an apocalyptic number.

21012111221220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21012111221220 is an abundant number, since it is smaller than the sum of its proper divisors (52498149923100).

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

21012111221220 is a wasteful number, since it uses less digits than its factorization.

21012111221220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 152993514 (or 152993509 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 18.

Adding to 21012111221220 its reverse (2212211121012), we get a palindrome (23224322342232).

The spelling of 21012111221220 in words is "twenty-one trillion, twelve billion, one hundred eleven million, two hundred twenty-one thousand, two hundred twenty".