18436718440 has 72 divisors (see below), whose sum is σ = 48271027410. Its totient is φ = 6319099584.

The previous prime is 18436718437. The next prime is 18436718453. The reversal of 18436718440 is 4481763481.

It can be written as a sum of positive squares in only one way, i.e., 16593046596 + 1843671844 = 128814^2 + 42938^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 6009787 + ... + 6012853.

Almost surely, 2^18436718440 is an apocalyptic number.

18436718440 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 18436718440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24135513705).

18436718440 is an abundant number, since it is smaller than the sum of its proper divisors (29834308970).

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

18436718440 is an frugal number, since it uses more digits than its factorization.

18436718440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6159 (or 3081 counting only the distinct ones).

The product of its (nonzero) digits is 516096, while the sum is 46.

The spelling of 18436718440 in words is "eighteen billion, four hundred thirty-six million, seven hundred eighteen thousand, four hundred forty".