18972291 has 16 divisors (see below), whose sum is σ = 27512576. Its totient is φ = 11559456.

The previous prime is 18972287. The next prime is 18972313. The reversal of 18972291 is 19227981.

It is not a de Polignac number, because 18972291 - 2² = 18972287 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is not an unprimeable number, because it can be changed into a prime (18972271) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1656 + ... + 6378.

It is an arithmetic number, because the mean of its divisors is an integer number (1719536).

Almost surely, 2^18972291 is an apocalyptic number.

18972291 is a deficient number, since it is larger than the sum of its proper divisors (8540285).

18972291 is a wasteful number, since it uses less digits than its factorization.

18972291 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4842.

The product of its digits is 18144, while the sum is 39.

The square root of 18972291 is about 4355.7193435758. The cubic root of 18972291 is about 266.7103846726.

The spelling of 18972291 in words is "eighteen million, nine hundred seventy-two thousand, two hundred ninety-one".