18151820 has 24 divisors (see below), whose sum is σ = 38238144. Its totient is φ = 7238016.

The previous prime is 18151799. The next prime is 18151849. The reversal of 18151820 is 2815181.

It is a self number, because there is not a number n which added to its sum of digits gives 18151820.

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, 6104 + ... + 8576.

It is an arithmetic number, because the mean of its divisors is an integer number (1593256).

Almost surely, 2^18151820 is an apocalyptic number.

18151820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18151820 is an abundant number, since it is smaller than the sum of its proper divisors (20086324).

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

18151820 is a wasteful number, since it uses less digits than its factorization.

18151820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2849 (or 2847 counting only the distinct ones).

The product of its (nonzero) digits is 640, while the sum is 26.

The square root of 18151820 is about 4260.4952763734. The cubic root of 18151820 is about 262.8088941171.

The spelling of 18151820 in words is "eighteen million, one hundred fifty-one thousand, eight hundred twenty".