21020521039 has 16 divisors (see below), whose sum is σ = 24453732160. Its totient is φ = 17696931840.

The previous prime is 21020521019. The next prime is 21020521051. The reversal of 21020521039 is 93012502012.

It is a happy number.

It is not a de Polignac number, because 21020521039 - 2⁵ = 21020521007 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21020521019) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 37807 + ... + 208495.

It is an arithmetic number, because the mean of its divisors is an integer number (1528358260).

Almost surely, 2^21020521039 is an apocalyptic number.

21020521039 is a deficient number, since it is larger than the sum of its proper divisors (3433211121).

21020521039 is a wasteful number, since it uses less digits than its factorization.

21020521039 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 171010.

The product of its (nonzero) digits is 1080, while the sum is 25.

The spelling of 21020521039 in words is "twenty-one billion, twenty million, five hundred twenty-one thousand, thirty-nine".