18644043870 has 72 divisors (see below), whose sum is σ = 50088882168. Its totient is φ = 4811343840.

The previous prime is 18644043863. The next prime is 18644043881. The reversal of 18644043870 is 7834044681.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 21292 + ... + 194271.

It is an arithmetic number, because the mean of its divisors is an integer number (695678919).

Almost surely, 2^18644043870 is an apocalyptic number.

18644043870 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 18644043870, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25044441084).

18644043870 is an abundant number, since it is smaller than the sum of its proper divisors (31444838298).

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

18644043870 is a wasteful number, since it uses less digits than its factorization.

18644043870 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 215638 (or 215604 counting only the distinct ones).

The product of its (nonzero) digits is 516096, while the sum is 45.

The spelling of 18644043870 in words is "eighteen billion, six hundred forty-four million, forty-three thousand, eight hundred seventy".