18161388 has 48 divisors (see below), whose sum is σ = 53813760. Its totient is φ = 5188752.

The previous prime is 18161387. The next prime is 18161393. The reversal of 18161388 is 88316181.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (18161383) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11256 + ... + 12767.

It is an arithmetic number, because the mean of its divisors is an integer number (1121120).

Almost surely, 2^18161388 is an apocalyptic number.

18161388 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

18161388 is an abundant number, since it is smaller than the sum of its proper divisors (35652372).

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

18161388 is a wasteful number, since it uses less digits than its factorization.

18161388 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24043 (or 24035 counting only the distinct ones).

The product of its digits is 9216, while the sum is 36.

The square root of 18161388 is about 4261.6180025901. The cubic root of 18161388 is about 262.8550623766.

The spelling of 18161388 in words is "eighteen million, one hundred sixty-one thousand, three hundred eighty-eight".