21716991995 has 4 divisors (see below), whose sum is σ = 26060390400. Its totient is φ = 17373593592.

The previous prime is 21716991953. The next prime is 21716992009. The reversal of 21716991995 is 59919961712.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21716991995 is a prime.

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, 2171699195 + ... + 2171699204.

It is an arithmetic number, because the mean of its divisors is an integer number (6515097600).

Almost surely, 2^21716991995 is an apocalyptic number.

21716991995 is a deficient number, since it is larger than the sum of its proper divisors (4343398405).

21716991995 is an equidigital number, since it uses as much as digits as its factorization.

21716991995 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4343398404.

The product of its digits is 2755620, while the sum is 59.

The spelling of 21716991995 in words is "twenty-one billion, seven hundred sixteen million, nine hundred ninety-one thousand, nine hundred ninety-five".