21703666720 has 24 divisors (see below), whose sum is σ = 51274913004. Its totient is φ = 8681466624.

The previous prime is 21703666717. The next prime is 21703666753. The reversal of 21703666720 is 2766630712.

It can be written as a sum of positive squares in 2 ways, for example, as 21516195856 + 187470864 = 146684^2 + 13692^2 .

It is a Harshad number since it is a multiple of its sum of digits (40).

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, 67823799 + ... + 67824118.

Almost surely, 2^21703666720 is an apocalyptic number.

21703666720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21703666720 is an abundant number, since it is smaller than the sum of its proper divisors (29571246284).

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

21703666720 is a wasteful number, since it uses less digits than its factorization.

21703666720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 135647932 (or 135647924 counting only the distinct ones).

The product of its (nonzero) digits is 127008, while the sum is 40.

The spelling of 21703666720 in words is "twenty-one billion, seven hundred three million, six hundred sixty-six thousand, seven hundred twenty".