21708643584 has 72 divisors (see below), whose sum is σ = 57800902432. Its totient is φ = 7233177600.

The previous prime is 21708643571. The next prime is 21708643601. The reversal of 21708643584 is 48534680712.

It is a Smith number, since the sum of its digits (48) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 2530887 + ... + 2539449.

Almost surely, 2^21708643584 is an apocalyptic number.

21708643584 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21708643584 is an abundant number, since it is smaller than the sum of its proper divisors (36092258848).

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

21708643584 is an equidigital number, since it uses as much as digits as its factorization.

21708643584 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11883 (or 11869 counting only the distinct ones).

The product of its (nonzero) digits is 1290240, while the sum is 48.

The spelling of 21708643584 in words is "twenty-one billion, seven hundred eight million, six hundred forty-three thousand, five hundred eighty-four".