21715290507 has 4 divisors (see below), whose sum is σ = 28953720680. Its totient is φ = 14476860336.

The previous prime is 21715290481. The next prime is 21715290517. The reversal of 21715290507 is 70509251712.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 21715290507 - 2²² = 21711096203 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21715290517) 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, 3619215082 + ... + 3619215087.

It is an arithmetic number, because the mean of its divisors is an integer number (7238430170).

Almost surely, 2^21715290507 is an apocalyptic number.

21715290507 is a deficient number, since it is larger than the sum of its proper divisors (7238430173).

21715290507 is an equidigital number, since it uses as much as digits as its factorization.

21715290507 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7238430172.

The product of its (nonzero) digits is 44100, while the sum is 39.

The spelling of 21715290507 in words is "twenty-one billion, seven hundred fifteen million, two hundred ninety thousand, five hundred seven".