21005367520 has 48 divisors (see below), whose sum is σ = 49683276720. Its totient is φ = 8392310784.

The previous prime is 21005367503. The next prime is 21005367547. The reversal of 21005367520 is 2576350012.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 61024 + ... + 213856.

It is an arithmetic number, because the mean of its divisors is an integer number (1035068265).

Almost surely, 2^21005367520 is an apocalyptic number.

21005367520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21005367520 is an abundant number, since it is smaller than the sum of its proper divisors (28677909200).

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

21005367520 is a wasteful number, since it uses less digits than its factorization.

21005367520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 153707 (or 153699 counting only the distinct ones).

The product of its (nonzero) digits is 12600, while the sum is 31.

The spelling of 21005367520 in words is "twenty-one billion, five million, three hundred sixty-seven thousand, five hundred twenty".