18187949 has 6 divisors (see below), whose sum is σ = 19694826. Its totient is φ = 16788720.

The previous prime is 18187937. The next prime is 18187973. The reversal of 18187949 is 94978181.

It can be written as a sum of positive squares in 3 ways, for example, as 184900 + 18003049 = 430^2 + 4243^2 .

It is not a de Polignac number, because 18187949 - 2¹² = 18183853 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18187249) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 53642 + ... + 53979.

It is an arithmetic number, because the mean of its divisors is an integer number (3282471).

Almost surely, 2^18187949 is an apocalyptic number.

It is an amenable number.

18187949 is a deficient number, since it is larger than the sum of its proper divisors (1506877).

18187949 is a wasteful number, since it uses less digits than its factorization.

18187949 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 107647 (or 107634 counting only the distinct ones).

The product of its digits is 145152, while the sum is 47.

The square root of 18187949 is about 4264.7331686754. The cubic root of 18187949 is about 262.9831416568.

The spelling of 18187949 in words is "eighteen million, one hundred eighty-seven thousand, nine hundred forty-nine".