18720156 has 144 divisors (see below), whose sum is σ = 57200640. Its totient is φ = 4717440.

The previous prime is 18720083. The next prime is 18720173. The reversal of 18720156 is 65102781.

It is a congruent number.

It is an unprimeable number.

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 47 ways as a sum of consecutive naturals, for example, 236925 + ... + 237003.

Almost surely, 2^18720156 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18720156, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28600320).

18720156 is an abundant number, since it is smaller than the sum of its proper divisors (38480484).

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

18720156 is a wasteful number, since it uses less digits than its factorization.

18720156 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 144 (or 135 counting only the distinct ones).

The product of its (nonzero) digits is 3360, while the sum is 30.

The square root of 18720156 is about 4326.6795582756. The cubic root of 18720156 is about 265.5236164139.

The spelling of 18720156 in words is "eighteen million, seven hundred twenty thousand, one hundred fifty-six".