21983680 has 28 divisors (see below), whose sum is σ = 52349400. Its totient is φ = 8793344.

The previous prime is 21983671. The next prime is 21983683. The reversal of 21983680 is 8638912.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21983683) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 34030 + ... + 34669.

Almost surely, 2^21983680 is an apocalyptic number.

21983680 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21983680 is an abundant number, since it is smaller than the sum of its proper divisors (30365720).

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

21983680 is an equidigital number, since it uses as much as digits as its factorization.

21983680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 68716 (or 68706 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 37.

The square root of 21983680 is about 4688.6757192197. The cubic root of 21983680 is about 280.1346291350.

The spelling of 21983680 in words is "twenty-one million, nine hundred eighty-three thousand, six hundred eighty".