21120210111021 has 16 divisors (see below), whose sum is σ = 33582445891584. Its totient is φ = 11543965774704.

The previous prime is 21120210110971. The next prime is 21120210111023. The reversal of 21120210111021 is 12011101202112.

It is a happy number.

It is not a de Polignac number, because 21120210111021 - 2⁷ = 21120210110893 is a prime.

It is a super-2 number, since 2×21120210111021² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21120210111023) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 21863571061 + ... + 21863572026.

It is an arithmetic number, because the mean of its divisors is an integer number (2098902868224).

Almost surely, 2^{21120210111021} is an apocalyptic number.

21120210111021 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21120210111021 is a deficient number, since it is larger than the sum of its proper divisors (12462235780563).

21120210111021 is a wasteful number, since it uses less digits than its factorization.

21120210111021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43727143120.

The product of its (nonzero) digits is 16, while the sum is 15.

Adding to 21120210111021 its reverse (12011101202112), we get a palindrome (33131311313133).

The spelling of 21120210111021 in words is "twenty-one trillion, one hundred twenty billion, two hundred ten million, one hundred eleven thousand, twenty-one".