18644294220 has 24 divisors (see below), whose sum is σ = 52204023984. Its totient is φ = 4971811776.

The previous prime is 18644294209. The next prime is 18644294231. The reversal of 18644294220 is 2249244681.

It is an interprime number because it is at equal distance from previous prime (18644294209) and next prime (18644294231).

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 155369059 + ... + 155369178.

It is an arithmetic number, because the mean of its divisors is an integer number (2175167666).

Almost surely, 2^18644294220 is an apocalyptic number.

18644294220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18644294220 is an abundant number, since it is smaller than the sum of its proper divisors (33559729764).

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

18644294220 is a wasteful number, since it uses less digits than its factorization.

18644294220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 310738249 (or 310738247 counting only the distinct ones).

The product of its (nonzero) digits is 221184, while the sum is 42.

The spelling of 18644294220 in words is "eighteen billion, six hundred forty-four million, two hundred ninety-four thousand, two hundred twenty".