18999157 has 4 divisors (see below), whose sum is σ = 19008576. Its totient is φ = 18989740.

The previous prime is 18999151. The next prime is 18999161. The reversal of 18999157 is 75199981.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18999157 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 18999157.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18999151) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 319 + ... + 6172.

It is an arithmetic number, because the mean of its divisors is an integer number (4752144).

Almost surely, 2^18999157 is an apocalyptic number.

It is an amenable number.

18999157 is a deficient number, since it is larger than the sum of its proper divisors (9419).

18999157 is an equidigital number, since it uses as much as digits as its factorization.

18999157 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9418.

The product of its digits is 204120, while the sum is 49.

The square root of 18999157 is about 4358.8022437362. The cubic root of 18999157 is about 266.8362183882.

The spelling of 18999157 in words is "eighteen million, nine hundred ninety-nine thousand, one hundred fifty-seven".