21697773408 has 36 divisors (see below), whose sum is σ = 61703043948. Its totient is φ = 7232591040.

The previous prime is 21697773401. The next prime is 21697773413. The reversal of 21697773408 is 80437779612.

21697773408 is a `hidden beast` number, since 2 + 169 + 7 + 7 + 73 + 408 = 666.

It is a tau number, because it is divible by the number of its divisors (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21697773401) 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 in 5 ways as a sum of consecutive naturals, for example, 37669458 + ... + 37670033.

It is an arithmetic number, because the mean of its divisors is an integer number (1713973443).

Almost surely, 2^21697773408 is an apocalyptic number.

It is an amenable number.

21697773408 is an abundant number, since it is smaller than the sum of its proper divisors (40005270540).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21697773408 is a wasteful number, since it uses less digits than its factorization.

21697773408 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 75339507 (or 75339496 counting only the distinct ones).

The product of its (nonzero) digits is 3556224, while the sum is 54.

The spelling of 21697773408 in words is "twenty-one billion, six hundred ninety-seven million, seven hundred seventy-three thousand, four hundred eight".