18532638440 has 64 divisors (see below), whose sum is σ = 43367788800. Its totient is φ = 7121357568.

The previous prime is 18532638379. The next prime is 18532638491. The reversal of 18532638440 is 4483623581.

It is a junction number, because it is equal to n+sod(n) for n = 18532638391 and 18532638400.

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, 37667 + ... + 196173.

It is an arithmetic number, because the mean of its divisors is an integer number (677621700).

Almost surely, 2^18532638440 is an apocalyptic number.

18532638440 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18532638440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21683894400).

18532638440 is an abundant number, since it is smaller than the sum of its proper divisors (24835150360).

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

18532638440 is a wasteful number, since it uses less digits than its factorization.

18532638440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 158634 (or 158630 counting only the distinct ones).

The product of its (nonzero) digits is 552960, while the sum is 44.

The spelling of 18532638440 in words is "eighteen billion, five hundred thirty-two million, six hundred thirty-eight thousand, four hundred forty".