18621139 has 2 divisors, whose sum is σ = 18621140. Its totient is φ = 18621138.

The previous prime is 18621091. The next prime is 18621143. The reversal of 18621139 is 93112681.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 18621139 - 2¹³ = 18612947 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 18621139.

It is not a weakly prime, because it can be changed into another prime (18621149) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9310569 + 9310570.

It is an arithmetic number, because the mean of its divisors is an integer number (9310570).

Almost surely, 2^18621139 is an apocalyptic number.

18621139 is a deficient number, since it is larger than the sum of its proper divisors (1).

18621139 is an equidigital number, since it uses as much as digits as its factorization.

18621139 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2592, while the sum is 31.

The square root of 18621139 is about 4315.2217787734. The cubic root of 18621139 is about 265.0546416338.

The spelling of 18621139 in words is "eighteen million, six hundred twenty-one thousand, one hundred thirty-nine".