18458991 has 12 divisors (see below), whose sum is σ = 28231632. Its totient is φ = 11582016.

The previous prime is 18458987. The next prime is 18459019. The reversal of 18458991 is 19985481.

It is not a de Polignac number, because 18458991 - 2² = 18458987 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18458941) 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, 60171 + ... + 60476.

It is an arithmetic number, because the mean of its divisors is an integer number (2352636).

Almost surely, 2^18458991 is an apocalyptic number.

18458991 is a deficient number, since it is larger than the sum of its proper divisors (9772641).

18458991 is a wasteful number, since it uses less digits than its factorization.

18458991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 120670 (or 120667 counting only the distinct ones).

The product of its digits is 103680, while the sum is 45.

The square root of 18458991 is about 4296.3927893059. The cubic root of 18458991 is about 264.2830555648.

The spelling of 18458991 in words is "eighteen million, four hundred fifty-eight thousand, nine hundred ninety-one".