21707664420 has 48 divisors (see below), whose sum is σ = 65456959680. Its totient is φ = 5343424896.

The previous prime is 21707664403. The next prime is 21707664439. The reversal of 21707664420 is 2446670712.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13914390 + ... + 13915949.

It is an arithmetic number, because the mean of its divisors is an integer number (1363686660).

Almost surely, 2^21707664420 is an apocalyptic number.

21707664420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21707664420 is an abundant number, since it is smaller than the sum of its proper divisors (43749295260).

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

21707664420 is a wasteful number, since it uses less digits than its factorization.

21707664420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27830364 (or 27830362 counting only the distinct ones).

The product of its (nonzero) digits is 112896, while the sum is 39.

The spelling of 21707664420 in words is "twenty-one billion, seven hundred seven million, six hundred sixty-four thousand, four hundred twenty".