18791397 has 12 divisors (see below), whose sum is σ = 27181440. Its totient is φ = 12509928.

The previous prime is 18791389. The next prime is 18791401. The reversal of 18791397 is 79319781.

It is not a de Polignac number, because 18791397 - 2³ = 18791389 is a prime.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18791317) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 9804 + ... + 11562.

It is an arithmetic number, because the mean of its divisors is an integer number (2265120).

Almost surely, 2^18791397 is an apocalyptic number.

It is an amenable number.

18791397 is a deficient number, since it is larger than the sum of its proper divisors (8390043).

18791397 is a wasteful number, since it uses less digits than its factorization.

18791397 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2952 (or 2949 counting only the distinct ones).

The product of its digits is 95256, while the sum is 45.

The square root of 18791397 is about 4334.9044972179. The cubic root of 18791397 is about 265.8600135912.

The spelling of 18791397 in words is "eighteen million, seven hundred ninety-one thousand, three hundred ninety-seven".