18990623 has 2 divisors, whose sum is σ = 18990624. Its totient is φ = 18990622.

The previous prime is 18990619. The next prime is 18990689. The reversal of 18990623 is 32609981.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 18990623 - 2² = 18990619 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18990613) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9495311 + 9495312.

It is an arithmetic number, because the mean of its divisors is an integer number (9495312).

Almost surely, 2^18990623 is an apocalyptic number.

18990623 is a deficient number, since it is larger than the sum of its proper divisors (1).

18990623 is an equidigital number, since it uses as much as digits as its factorization.

18990623 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 23328, while the sum is 38.

The square root of 18990623 is about 4357.8231951285. The cubic root of 18990623 is about 266.7962601009.

The spelling of 18990623 in words is "eighteen million, nine hundred ninety thousand, six hundred twenty-three".