21112111020 has 192 divisors, whose sum is σ = 79369952256. Its totient is φ = 4049464320.

The previous prime is 21112111019. The next prime is 21112111021. The reversal of 21112111020 is 2011121112.

It is an interprime number because it is at equal distance from previous prime (21112111019) and next prime (21112111021).

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a junction number, because it is equal to n+sod(n) for n = 21112110987 and 21112111005.

It is not an unprimeable number, because it can be changed into a prime (21112111021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 115699 + ... + 235818.

It is an arithmetic number, because the mean of its divisors is an integer number (413385168).

Almost surely, 2^21112111020 is an apocalyptic number.

21112111020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21112111020 is an abundant number, since it is smaller than the sum of its proper divisors (58257841236).

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

21112111020 is a wasteful number, since it uses less digits than its factorization.

21112111020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 351560 (or 351558 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 12.

Adding to 21112111020 its reverse (2011121112), we get a palindrome (23123232132).

The spelling of 21112111020 in words is "twenty-one billion, one hundred twelve million, one hundred eleven thousand, twenty".