21120101020 has 24 divisors (see below), whose sum is σ = 45383660784. Its totient is φ = 8251574016.

The previous prime is 21120100987. The next prime is 21120101071. The reversal of 21120101020 is 2010102112.

It is a Harshad number since it is a multiple of its sum of digits (10).

It is a junction number, because it is equal to n+sod(n) for n = 21120100988 and 21120101006.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 12278269 + ... + 12279988.

It is an arithmetic number, because the mean of its divisors is an integer number (1890985866).

Almost surely, 2^21120101020 is an apocalyptic number.

21120101020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21120101020 is an abundant number, since it is smaller than the sum of its proper divisors (24263559764).

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

21120101020 is a wasteful number, since it uses less digits than its factorization.

21120101020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24558309 (or 24558307 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 10.

Adding to 21120101020 its reverse (2010102112), we get a palindrome (23130203132).

The spelling of 21120101020 in words is "twenty-one billion, one hundred twenty million, one hundred one thousand, twenty".