21247762180 has 24 divisors (see below), whose sum is σ = 44652668760. Its totient is φ = 8492939520.

The previous prime is 21247762157. The next prime is 21247762199. The reversal of 21247762180 is 8126774212.

It can be written as a sum of positive squares in 4 ways, for example, as 115906756 + 21131855424 = 10766^2 + 145368^2 .

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, 357025 + ... + 412264.

It is an arithmetic number, because the mean of its divisors is an integer number (1860527865).

Almost surely, 2^21247762180 is an apocalyptic number.

21247762180 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21247762180 is an abundant number, since it is smaller than the sum of its proper divisors (23404906580).

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

21247762180 is a wasteful number, since it uses less digits than its factorization.

21247762180 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 770679 (or 770677 counting only the distinct ones).

The product of its (nonzero) digits is 75264, while the sum is 40.

The spelling of 21247762180 in words is "twenty-one billion, two hundred forty-seven million, seven hundred sixty-two thousand, one hundred eighty".