21993697775 has 36 divisors (see below), whose sum is σ = 31762277352. Its totient is φ = 15063572160.

The previous prime is 21993697757. The next prime is 21993697783. The reversal of 21993697775 is 57779639912.

It is not a de Polignac number, because 21993697775 - 2¹⁶ = 21993632239 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 1071509 + ... + 1091841.

It is an arithmetic number, because the mean of its divisors is an integer number (882285482).

Almost surely, 2^21993697775 is an apocalyptic number.

21993697775 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21993697775 is a deficient number, since it is larger than the sum of its proper divisors (9768579577).

21993697775 is a wasteful number, since it uses less digits than its factorization.

21993697775 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21240 (or 21228 counting only the distinct ones).

The product of its digits is 45008460, while the sum is 65.

The spelling of 21993697775 in words is "twenty-one billion, nine hundred ninety-three million, six hundred ninety-seven thousand, seven hundred seventy-five".