18537720640 has 56 divisors (see below), whose sum is σ = 44170850952. Its totient is φ = 7410401280.

The previous prime is 18537720637. The next prime is 18537720653. The reversal of 18537720640 is 4602773581.

It can be written as a sum of positive squares in 4 ways, for example, as 590295616 + 17947425024 = 24296^2 + 133968^2 .

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, 512760 + ... + 547720.

Almost surely, 2^18537720640 is an apocalyptic number.

18537720640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18537720640 is an abundant number, since it is smaller than the sum of its proper divisors (25633130312).

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

18537720640 is a wasteful number, since it uses less digits than its factorization.

18537720640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36635 (or 36625 counting only the distinct ones).

The product of its (nonzero) digits is 282240, while the sum is 43.

The spelling of 18537720640 in words is "eighteen billion, five hundred thirty-seven million, seven hundred twenty thousand, six hundred forty".