21700989780 has 24 divisors (see below), whose sum is σ = 60762771552. Its totient is φ = 5786930592.

The previous prime is 21700989721. The next prime is 21700989811. The reversal of 21700989780 is 8798900712.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 180841522 + ... + 180841641.

It is an arithmetic number, because the mean of its divisors is an integer number (2531782148).

Almost surely, 2^21700989780 is an apocalyptic number.

21700989780 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21700989780 is an abundant number, since it is smaller than the sum of its proper divisors (39061781772).

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

21700989780 is a wasteful number, since it uses less digits than its factorization.

21700989780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 361683175 (or 361683173 counting only the distinct ones).

The product of its (nonzero) digits is 508032, while the sum is 51.

The spelling of 21700989780 in words is "twenty-one billion, seven hundred million, nine hundred eighty-nine thousand, seven hundred eighty".