18999913 has 2 divisors, whose sum is σ = 18999914. Its totient is φ = 18999912.

The previous prime is 18999889. The next prime is 18999919. The reversal of 18999913 is 31999981.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17530969 + 1468944 = 4187^2 + 1212^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18999913 is a prime.

It is not a weakly prime, because it can be changed into another prime (18999919) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9499956 + 9499957.

It is an arithmetic number, because the mean of its divisors is an integer number (9499957).

Almost surely, 2^18999913 is an apocalyptic number.

It is an amenable number.

18999913 is a deficient number, since it is larger than the sum of its proper divisors (1).

18999913 is an equidigital number, since it uses as much as digits as its factorization.

18999913 is an evil number, because the sum of its binary digits is even.

The product of its digits is 157464, while the sum is 49.

The square root of 18999913 is about 4358.8889639448. Note that the first 3 decimals coincide. The cubic root of 18999913 is about 266.8397575892.

The spelling of 18999913 in words is "eighteen million, nine hundred ninety-nine thousand, nine hundred thirteen".