21488931840 has 88 divisors (see below), whose sum is σ = 68731054560. Its totient is φ = 5730377728.

The previous prime is 21488931839. The next prime is 21488931851. The reversal of 21488931840 is 4813988412.

It is a happy number.

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

It is a self number, because there is not a number n which added to its sum of digits gives 21488931840.

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, 684150 + ... + 714869.

Almost surely, 2^21488931840 is an apocalyptic number.

21488931840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21488931840 is an abundant number, since it is smaller than the sum of its proper divisors (47242122720).

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

21488931840 is a wasteful number, since it uses less digits than its factorization.

21488931840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1399047 (or 1399029 counting only the distinct ones).

The product of its (nonzero) digits is 442368, while the sum is 48.

The spelling of 21488931840 in words is "twenty-one billion, four hundred eighty-eight million, nine hundred thirty-one thousand, eight hundred forty".