18449881949 has 2 divisors, whose sum is σ = 18449881950. Its totient is φ = 18449881948.

The previous prime is 18449881897. The next prime is 18449881969. The reversal of 18449881949 is 94918894481.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16190781049 + 2259100900 = 127243^2 + 47530^2 .

It is a cyclic number.

It is not a de Polignac number, because 18449881949 - 2²⁰ = 18448833373 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18449881969) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9224940974 + 9224940975.

It is an arithmetic number, because the mean of its divisors is an integer number (9224940975).

Almost surely, 2^18449881949 is an apocalyptic number.

It is an amenable number.

18449881949 is a deficient number, since it is larger than the sum of its proper divisors (1).

18449881949 is an equidigital number, since it uses as much as digits as its factorization.

18449881949 is an evil number, because the sum of its binary digits is even.

The product of its digits is 23887872, while the sum is 65.

The spelling of 18449881949 in words is "eighteen billion, four hundred forty-nine million, eight hundred eighty-one thousand, nine hundred forty-nine".