21022072917 has 4 divisors (see below), whose sum is σ = 28029430560. Its totient is φ = 14014715276.

The previous prime is 21022072901. The next prime is 21022072987. The reversal of 21022072917 is 71927022012.

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 not a de Polignac number, because 21022072917 - 2⁴ = 21022072901 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21022072987) 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, 3503678817 + ... + 3503678822.

It is an arithmetic number, because the mean of its divisors is an integer number (7007357640).

Almost surely, 2^21022072917 is an apocalyptic number.

It is an amenable number.

21022072917 is a deficient number, since it is larger than the sum of its proper divisors (7007357643).

21022072917 is an equidigital number, since it uses as much as digits as its factorization.

21022072917 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7007357642.

The product of its (nonzero) digits is 7056, while the sum is 33.

Adding to 21022072917 its reverse (71927022012), we get a palindrome (92949094929).

The spelling of 21022072917 in words is "twenty-one billion, twenty-two million, seventy-two thousand, nine hundred seventeen".