18997633 has 2 divisors, whose sum is σ = 18997634. Its totient is φ = 18997632.

The previous prime is 18997631. The next prime is 18997661. The reversal of 18997633 is 33679981.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18173169 + 824464 = 4263^2 + 908^2 .

It is a cyclic number.

It is not a de Polignac number, because 18997633 - 2¹ = 18997631 is a prime.

Together with 18997631, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (18997631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9498816 + 9498817.

It is an arithmetic number, because the mean of its divisors is an integer number (9498817).

Almost surely, 2^18997633 is an apocalyptic number.

It is an amenable number.

18997633 is a deficient number, since it is larger than the sum of its proper divisors (1).

18997633 is an equidigital number, since it uses as much as digits as its factorization.

18997633 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 244944, while the sum is 46.

The square root of 18997633 is about 4358.6274215629. The cubic root of 18997633 is about 266.8290835231.

The spelling of 18997633 in words is "eighteen million, nine hundred ninety-seven thousand, six hundred thirty-three".