18109440 has 176 divisors, whose sum is σ = 64848960. Its totient is φ = 4792320.

The previous prime is 18109423. The next prime is 18109457. The reversal of 18109440 is 4490181.

It is an interprime number because it is at equal distance from previous prime (18109423) and next prime (18109457).

It is a super-2 number, since 2×18109440² = 655903634227200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

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, 138175 + ... + 138305.

It is an arithmetic number, because the mean of its divisors is an integer number (368460).

Almost surely, 2^18109440 is an apocalyptic number.

18109440 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18109440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32424480).

18109440 is an abundant number, since it is smaller than the sum of its proper divisors (46739520).

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

18109440 is a wasteful number, since it uses less digits than its factorization.

18109440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 165 (or 141 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 27.

The square root of 18109440 is about 4255.5187697859. The cubic root of 18109440 is about 262.6042035272.

The spelling of 18109440 in words is "eighteen million, one hundred nine thousand, four hundred forty".