21056124620 has 24 divisors (see below), whose sum is σ = 44240288400. Its totient is φ = 8418178112.

The previous prime is 21056124601. The next prime is 21056124623. The reversal of 21056124620 is 2642165012.

It is not an unprimeable number, because it can be changed into a prime (21056124623) 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 7 ways as a sum of consecutive naturals, for example, 226415 + ... + 305574.

It is an arithmetic number, because the mean of its divisors is an integer number (1843345350).

Almost surely, 2^21056124620 is an apocalyptic number.

21056124620 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21056124620 is an abundant number, since it is smaller than the sum of its proper divisors (23184163780).

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

21056124620 is a wasteful number, since it uses less digits than its factorization.

21056124620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 533977 (or 533975 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 29.

Adding to 21056124620 its reverse (2642165012), we get a palindrome (23698289632).

The spelling of 21056124620 in words is "twenty-one billion, fifty-six million, one hundred twenty-four thousand, six hundred twenty".