18159440 has 80 divisors (see below), whose sum is σ = 47913600. Its totient is φ = 6345216.

The previous prime is 18159431. The next prime is 18159461. The reversal of 18159440 is 4495181.

It is a tau number, because it is divible by the number of its divisors (80).

It is a super-2 number, since 2×18159440² = 659530522227200, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 18159397 and 18159406.

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, 19301 + ... + 20219.

It is an arithmetic number, because the mean of its divisors is an integer number (598920).

Almost surely, 2^18159440 is an apocalyptic number.

18159440 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 18159440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23956800).

18159440 is an abundant number, since it is smaller than the sum of its proper divisors (29754160).

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

18159440 is a wasteful number, since it uses less digits than its factorization.

18159440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 964 (or 958 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 32.

The square root of 18159440 is about 4261.3894447703. The cubic root of 18159440 is about 262.8456640500.

The spelling of 18159440 in words is "eighteen million, one hundred fifty-nine thousand, four hundred forty".