21731322648 has 64 divisors (see below), whose sum is σ = 64092395520. Its totient is φ = 6008659200.

The previous prime is 21731322631. The next prime is 21731322653. The reversal of 21731322648 is 84622313712.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

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, 2081133 + ... + 2091548.

It is an arithmetic number, because the mean of its divisors is an integer number (1001443680).

Almost surely, 2^21731322648 is an apocalyptic number.

21731322648 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

21731322648 is an abundant number, since it is smaller than the sum of its proper divisors (42361072872).

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

21731322648 is a wasteful number, since it uses less digits than its factorization.

21731322648 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4172728 (or 4172724 counting only the distinct ones).

The product of its digits is 96768, while the sum is 39.

The spelling of 21731322648 in words is "twenty-one billion, seven hundred thirty-one million, three hundred twenty-two thousand, six hundred forty-eight".