18644021490 has 32 divisors (see below), whose sum is σ = 46691116416. Its totient is φ = 4755576320.

The previous prime is 18644021477. The next prime is 18644021503. The reversal of 18644021490 is 9412044681.

It is an interprime number because it is at equal distance from previous prime (18644021477) and next prime (18644021503).

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, 13509471 + ... + 13510850.

It is an arithmetic number, because the mean of its divisors is an integer number (1459097388).

Almost surely, 2^18644021490 is an apocalyptic number.

18644021490 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

18644021490 is an abundant number, since it is smaller than the sum of its proper divisors (28047094926).

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

18644021490 is a wasteful number, since it uses less digits than its factorization.

18644021490 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27020354.

The product of its (nonzero) digits is 55296, while the sum is 39.

The spelling of 18644021490 in words is "eighteen billion, six hundred forty-four million, twenty-one thousand, four hundred ninety".