18621899 has 2 divisors, whose sum is σ = 18621900. Its totient is φ = 18621898.

The previous prime is 18621877. The next prime is 18621901. The reversal of 18621899 is 99812681.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 18621899 - 2²⁴ = 1844683 is a prime.

Together with 18621901, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (18621839) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9310949 + 9310950.

It is an arithmetic number, because the mean of its divisors is an integer number (9310950).

Almost surely, 2^18621899 is an apocalyptic number.

18621899 is a deficient number, since it is larger than the sum of its proper divisors (1).

18621899 is an equidigital number, since it uses as much as digits as its factorization.

18621899 is an evil number, because the sum of its binary digits is even.

The product of its digits is 62208, while the sum is 44.

The square root of 18621899 is about 4315.3098382387. The cubic root of 18621899 is about 265.0582475498.

The spelling of 18621899 in words is "eighteen million, six hundred twenty-one thousand, eight hundred ninety-nine".