18991293 has 16 divisors (see below), whose sum is σ = 25883136. Its totient is φ = 12383280.

The previous prime is 18991283. The next prime is 18991303. The reversal of 18991293 is 39219981.

It is an interprime number because it is at equal distance from previous prime (18991283) and next prime (18991303).

It is not a de Polignac number, because 18991293 - 2⁶ = 18991229 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18991213) 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, 34446 + ... + 34992.

It is an arithmetic number, because the mean of its divisors is an integer number (1617696).

Almost surely, 2^18991293 is an apocalyptic number.

It is an amenable number.

18991293 is a deficient number, since it is larger than the sum of its proper divisors (6891843).

18991293 is a wasteful number, since it uses less digits than its factorization.

18991293 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 784.

The product of its digits is 34992, while the sum is 42.

The square root of 18991293 is about 4357.9000676932. The cubic root of 18991293 is about 266.7993976387.

The spelling of 18991293 in words is "eighteen million, nine hundred ninety-one thousand, two hundred ninety-three".