18115939 has 2 divisors, whose sum is σ = 18115940. Its totient is φ = 18115938.

The previous prime is 18115919. The next prime is 18115967. The reversal of 18115939 is 93951181.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 18115939 - 2⁵ = 18115907 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 18115898 and 18115907.

It is not a weakly prime, because it can be changed into another prime (18115919) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9057969 + 9057970.

It is an arithmetic number, because the mean of its divisors is an integer number (9057970).

Almost surely, 2^18115939 is an apocalyptic number.

18115939 is a deficient number, since it is larger than the sum of its proper divisors (1).

18115939 is an equidigital number, since it uses as much as digits as its factorization.

18115939 is an evil number, because the sum of its binary digits is even.

The product of its digits is 9720, while the sum is 37.

The square root of 18115939 is about 4256.2822979685. The cubic root of 18115939 is about 262.6356136758.

It can be divided in two parts, 1811 and 5939, that added together give a triangular number (7750 = T₁₂₄).

The spelling of 18115939 in words is "eighteen million, one hundred fifteen thousand, nine hundred thirty-nine".