18158720 has 64 divisors (see below), whose sum is σ = 45991800. Its totient is φ = 6832128.

The previous prime is 18158719. The next prime is 18158731. The reversal of 18158720 is 2785181.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 16581184 + 1577536 = 4072^2 + 1256^2 .

It is a tau number, because it is divible by the number of its divisors (64).

It is a super-2 number, since 2×18158720² = 659478224076800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (32).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10046 + ... + 11714.

Almost surely, 2^18158720 is an apocalyptic number.

18158720 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 18158720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22995900).

18158720 is an abundant number, since it is smaller than the sum of its proper divisors (27833080).

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

18158720 is a wasteful number, since it uses less digits than its factorization.

18158720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1705 (or 1693 counting only the distinct ones).

The product of its (nonzero) digits is 4480, while the sum is 32.

The square root of 18158720 is about 4261.3049644446. The cubic root of 18158720 is about 262.8421901657.

The spelling of 18158720 in words is "eighteen million, one hundred fifty-eight thousand, seven hundred twenty".