21724747040 has 24 divisors (see below), whose sum is σ = 51324715260. Its totient is φ = 8689898752.

The previous prime is 21724747019. The next prime is 21724747073. The reversal of 21724747040 is 4074742712.

It can be written as a sum of positive squares in 2 ways, for example, as 20820181264 + 904565776 = 144292^2 + 30076^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21724746985 and 21724747003.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 67889675 + ... + 67889994.

Almost surely, 2^21724747040 is an apocalyptic number.

21724747040 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21724747040 is an abundant number, since it is smaller than the sum of its proper divisors (29599968220).

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

21724747040 is a wasteful number, since it uses less digits than its factorization.

21724747040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 135779684 (or 135779676 counting only the distinct ones).

The product of its (nonzero) digits is 87808, while the sum is 38.

The spelling of 21724747040 in words is "twenty-one billion, seven hundred twenty-four million, seven hundred forty-seven thousand, forty".