21022072915 has 4 divisors (see below), whose sum is σ = 25226487504. Its totient is φ = 16817658328.

The previous prime is 21022072901. The next prime is 21022072987. The reversal of 21022072915 is 51927022012.

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

It is a cyclic number.

It is not a de Polignac number, because 21022072915 - 2¹⁹ = 21021548627 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2102207287 + ... + 2102207296.

It is an arithmetic number, because the mean of its divisors is an integer number (6306621876).

Almost surely, 2^21022072915 is an apocalyptic number.

21022072915 is a deficient number, since it is larger than the sum of its proper divisors (4204414589).

21022072915 is an equidigital number, since it uses as much as digits as its factorization.

21022072915 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4204414588.

The product of its (nonzero) digits is 5040, while the sum is 31.

Adding to 21022072915 its reverse (51927022012), we get a palindrome (72949094927).

The spelling of 21022072915 in words is "twenty-one billion, twenty-two million, seventy-two thousand, nine hundred fifteen".