18491944193 has 2 divisors, whose sum is σ = 18491944194. Its totient is φ = 18491944192.

The previous prime is 18491944139. The next prime is 18491944213. The reversal of 18491944193 is 39144919481.

It is a happy number.

Together with previous prime (18491944139) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14464391824 + 4027552369 = 120268^2 + 63463^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18491944193 is a prime.

It is not a weakly prime, because it can be changed into another prime (18491940193) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9245972096 + 9245972097.

It is an arithmetic number, because the mean of its divisors is an integer number (9245972097).

Almost surely, 2^18491944193 is an apocalyptic number.

It is an amenable number.

18491944193 is a deficient number, since it is larger than the sum of its proper divisors (1).

18491944193 is an equidigital number, since it uses as much as digits as its factorization.

18491944193 is an evil number, because the sum of its binary digits is even.

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

The spelling of 18491944193 in words is "eighteen billion, four hundred ninety-one million, nine hundred forty-four thousand, one hundred ninety-three".