18915420 has 24 divisors (see below), whose sum is σ = 52963344. Its totient is φ = 5044096.

The previous prime is 18915419. The next prime is 18915433. The reversal of 18915420 is 2451981.

It is a happy number.

It is a super-2 number, since 2×18915420² = 715586227552800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

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, 157569 + ... + 157688.

It is an arithmetic number, because the mean of its divisors is an integer number (2206806).

Almost surely, 2^18915420 is an apocalyptic number.

18915420 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18915420 is an abundant number, since it is smaller than the sum of its proper divisors (34047924).

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

18915420 is a wasteful number, since it uses less digits than its factorization.

18915420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 315269 (or 315267 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 30.

The square root of 18915420 is about 4349.1861307606. The cubic root of 18915420 is about 266.4436225222.

The spelling of 18915420 in words is "eighteen million, nine hundred fifteen thousand, four hundred twenty".