18972155 has 8 divisors (see below), whose sum is σ = 23501184. Its totient is φ = 14688000.

The previous prime is 18972137. The next prime is 18972169. The reversal of 18972155 is 55127981.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 18972155 - 2⁶ = 18972091 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 61046 + ... + 61355.

It is an arithmetic number, because the mean of its divisors is an integer number (2937648).

Almost surely, 2^18972155 is an apocalyptic number.

18972155 is a deficient number, since it is larger than the sum of its proper divisors (4529029).

18972155 is a wasteful number, since it uses less digits than its factorization.

18972155 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 122437.

The product of its digits is 25200, while the sum is 38.

The square root of 18972155 is about 4355.7037318899. The cubic root of 18972155 is about 266.7097473801.

The spelling of 18972155 in words is "eighteen million, nine hundred seventy-two thousand, one hundred fifty-five".