18936253640 has 16 divisors (see below), whose sum is σ = 42606570780. Its totient is φ = 7574501440.

The previous prime is 18936253639. The next prime is 18936253657. The reversal of 18936253640 is 4635263981.

It can be written as a sum of positive squares in 2 ways, for example, as 18934310404 + 1943236 = 137602^2 + 1394^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 236703131 + ... + 236703210.

Almost surely, 2^18936253640 is an apocalyptic number.

18936253640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18936253640 is an abundant number, since it is smaller than the sum of its proper divisors (23670317140).

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

18936253640 is a wasteful number, since it uses less digits than its factorization.

18936253640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 473406352 (or 473406348 counting only the distinct ones).

The product of its (nonzero) digits is 933120, while the sum is 47.

The spelling of 18936253640 in words is "eighteen billion, nine hundred thirty-six million, two hundred fifty-three thousand, six hundred forty".