21170520337 has 4 divisors (see below), whose sum is σ = 21259100160. Its totient is φ = 21081940516.

The previous prime is 21170520317. The next prime is 21170520367. The reversal of 21170520337 is 73302507112.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21170520337 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21170520299 and 21170520308.

It is not an unprimeable number, because it can be changed into a prime (21170520317) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 44289553 + ... + 44290030.

It is an arithmetic number, because the mean of its divisors is an integer number (5314775040).

Almost surely, 2^21170520337 is an apocalyptic number.

It is an amenable number.

21170520337 is a deficient number, since it is larger than the sum of its proper divisors (88579823).

21170520337 is an equidigital number, since it uses as much as digits as its factorization.

21170520337 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 88579822.

The product of its (nonzero) digits is 8820, while the sum is 31.

The spelling of 21170520337 in words is "twenty-one billion, one hundred seventy million, five hundred twenty thousand, three hundred thirty-seven".