21907516723 has 2 divisors, whose sum is σ = 21907516724. Its totient is φ = 21907516722.

The previous prime is 21907516717. The next prime is 21907516783. The reversal of 21907516723 is 32761570912.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21907516723 - 2⁵ = 21907516691 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21907516723.

It is not a weakly prime, because it can be changed into another prime (21907516703) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10953758361 + 10953758362.

It is an arithmetic number, because the mean of its divisors is an integer number (10953758362).

Almost surely, 2^21907516723 is an apocalyptic number.

21907516723 is a deficient number, since it is larger than the sum of its proper divisors (1).

21907516723 is an equidigital number, since it uses as much as digits as its factorization.

21907516723 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 158760, while the sum is 43.

The spelling of 21907516723 in words is "twenty-one billion, nine hundred seven million, five hundred sixteen thousand, seven hundred twenty-three".