21105020620 has 24 divisors (see below), whose sum is σ = 44543268000. Its totient is φ = 8399584512.

The previous prime is 21105020611. The next prime is 21105020681. The reversal of 21105020620 is 2602050112.

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, 2647405 + ... + 2655364.

It is an arithmetic number, because the mean of its divisors is an integer number (1855969500).

Almost surely, 2^21105020620 is an apocalyptic number.

21105020620 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21105020620 is an abundant number, since it is smaller than the sum of its proper divisors (23438247380).

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

21105020620 is a wasteful number, since it uses less digits than its factorization.

21105020620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5302977 (or 5302975 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 19.

Adding to 21105020620 its reverse (2602050112), we get a palindrome (23707070732).

The spelling of 21105020620 in words is "twenty-one billion, one hundred five million, twenty thousand, six hundred twenty".