21111221201220 has 36 divisors (see below), whose sum is σ = 64037370977580. Its totient is φ = 5629658986944.

The previous prime is 21111221201177. The next prime is 21111221201269. The reversal of 21111221201220 is 2210212211112.

21111221201220 is a `hidden beast` number, since 2 + 11 + 11 + 221 + 201 + 220 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 2495085613056 + 18616135588164 = 1579584^2 + 4314642^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a super-3 number, since 3×21111221201220³ (a number of 41 digits) contains 333 as substring.

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 = 21111221201193 and 21111221201202.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 58642280935 + ... + 58642281294.

Almost surely, 2^{21111221201220} is an apocalyptic number.

21111221201220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21111221201220 is an abundant number, since it is smaller than the sum of its proper divisors (42926149776360).

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

21111221201220 is a wasteful number, since it uses less digits than its factorization.

21111221201220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 117284562244 (or 117284562239 counting only the distinct ones).

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

Adding to 21111221201220 its reverse (2210212211112), we get a palindrome (23321433412332).

The spelling of 21111221201220 in words is "twenty-one trillion, one hundred eleven billion, two hundred twenty-one million, two hundred one thousand, two hundred twenty".