21123112011020 has 24 divisors (see below), whose sum is σ = 44359426427568. Its totient is φ = 8449075051200.

The previous prime is 21123112011011. The next prime is 21123112011061. The reversal of 21123112011020 is 2011021132112.

It is a happy number.

It is a super-2 number, since 2×21123112011020² (a number of 27 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21123112011020.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9586811 + ... + 11582450.

It is an arithmetic number, because the mean of its divisors is an integer number (1848309434482).

Almost surely, 2^{21123112011020} is an apocalyptic number.

21123112011020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21123112011020 is an abundant number, since it is smaller than the sum of its proper divisors (23236314416548).

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

21123112011020 is a wasteful number, since it uses less digits than its factorization.

21123112011020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21219161 (or 21219159 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 17.

Adding to 21123112011020 its reverse (2011021132112), we get a palindrome (23134133143132).

The spelling of 21123112011020 in words is "twenty-one trillion, one hundred twenty-three billion, one hundred twelve million, eleven thousand, twenty".