18491944139 has 2 divisors, whose sum is σ = 18491944140. Its totient is φ = 18491944138.

The previous prime is 18491944127. The next prime is 18491944193. The reversal of 18491944139 is 93144919481.

It is a happy number.

Together with next prime (18491944193) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 18491944139 - 2²⁴ = 18475166923 is a prime.

It is not a weakly prime, because it can be changed into another prime (18491944739) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9245972069 + 9245972070.

It is an arithmetic number, because the mean of its divisors is an integer number (9245972070).

Almost surely, 2^18491944139 is an apocalyptic number.

18491944139 is a deficient number, since it is larger than the sum of its proper divisors (1).

18491944139 is an equidigital number, since it uses as much as digits as its factorization.

18491944139 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1119744, while the sum is 53.

The spelling of 18491944139 in words is "eighteen billion, four hundred ninety-one million, nine hundred forty-four thousand, one hundred thirty-nine".