21520530331505 has 32 divisors (see below), whose sum is σ = 27104853654528. Its totient is φ = 16381782662400.

The previous prime is 21520530331481. The next prime is 21520530331511. The reversal of 21520530331505 is 50513303502512.

It is not a de Polignac number, because 21520530331505 - 2²⁰ = 21520529282929 is a prime.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 24885914 + ... + 25736156.

It is an arithmetic number, because the mean of its divisors is an integer number (847026676704).

Almost surely, 2^{21520530331505} is an apocalyptic number.

It is an amenable number.

21520530331505 is a deficient number, since it is larger than the sum of its proper divisors (5584323323023).

21520530331505 is a wasteful number, since it uses less digits than its factorization.

21520530331505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 853017.

The product of its (nonzero) digits is 67500, while the sum is 35.

The spelling of 21520530331505 in words is "twenty-one trillion, five hundred twenty billion, five hundred thirty million, three hundred thirty-one thousand, five hundred five".