18723139 has 2 divisors, whose sum is σ = 18723140. Its totient is φ = 18723138.

The previous prime is 18723121. The next prime is 18723143. The reversal of 18723139 is 93132781.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 18723139 - 2⁷ = 18723011 is a prime.

It is equal to p_1194487 and since 18723139 and 1194487 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (18723109) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9361569 + 9361570.

It is an arithmetic number, because the mean of its divisors is an integer number (9361570).

Almost surely, 2^18723139 is an apocalyptic number.

18723139 is a deficient number, since it is larger than the sum of its proper divisors (1).

18723139 is an equidigital number, since it uses as much as digits as its factorization.

18723139 is an evil number, because the sum of its binary digits is even.

The product of its digits is 9072, while the sum is 34.

The square root of 18723139 is about 4327.0242661672. The cubic root of 18723139 is about 265.5377191254.

The spelling of 18723139 in words is "eighteen million, seven hundred twenty-three thousand, one hundred thirty-nine".