21000520015 has 8 divisors (see below), whose sum is σ = 25233229728. Its totient is φ = 16778678880.

The previous prime is 21000520007. The next prime is 21000520033. The reversal of 21000520015 is 51002500012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21000520015 - 2³ = 21000520007 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2712891 + ... + 2720620.

It is an arithmetic number, because the mean of its divisors is an integer number (3154153716).

Almost surely, 2^21000520015 is an apocalyptic number.

21000520015 is a deficient number, since it is larger than the sum of its proper divisors (4232709713).

21000520015 is an equidigital number, since it uses as much as digits as its factorization.

21000520015 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5434289.

The product of its (nonzero) digits is 100, while the sum is 16.

The spelling of 21000520015 in words is "twenty-one billion, five hundred twenty thousand, fifteen".