21976499691 has 10 divisors (see below), whose sum is σ = 32829092252. Its totient is φ = 14650999740.

The previous prime is 21976499651. The next prime is 21976499711. The reversal of 21976499691 is 19699467912.

21976499691 is a `hidden beast` number, since 2 + 19 + 76 + 499 + 69 + 1 = 666.

It is not a de Polignac number, because 21976499691 - 2⁹ = 21976499179 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21976499651) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 135657325 + ... + 135657486.

Almost surely, 2^21976499691 is an apocalyptic number.

21976499691 is a deficient number, since it is larger than the sum of its proper divisors (10852592561).

21976499691 is an equidigital number, since it uses as much as digits as its factorization.

21976499691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 271314823 (or 271314814 counting only the distinct ones).

The product of its digits is 13226976, while the sum is 63.

The spelling of 21976499691 in words is "twenty-one billion, nine hundred seventy-six million, four hundred ninety-nine thousand, six hundred ninety-one".