18187649 has 2 divisors, whose sum is σ = 18187650. Its totient is φ = 18187648.

The previous prime is 18187627. The next prime is 18187651. The reversal of 18187649 is 94678181.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16056049 + 2131600 = 4007^2 + 1460^2 .

It is a cyclic number.

It is not a de Polignac number, because 18187649 - 2¹⁶ = 18122113 is a prime.

It is a super-2 number, since 2×18187649² = 661581152294402, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 18187651, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (18187249) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9093824 + 9093825.

It is an arithmetic number, because the mean of its divisors is an integer number (9093825).

Almost surely, 2^18187649 is an apocalyptic number.

It is an amenable number.

18187649 is a deficient number, since it is larger than the sum of its proper divisors (1).

18187649 is an equidigital number, since it uses as much as digits as its factorization.

18187649 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 96768, while the sum is 44.

The square root of 18187649 is about 4264.6979963416. The cubic root of 18187649 is about 262.9816957291.

The spelling of 18187649 in words is "eighteen million, one hundred eighty-seven thousand, six hundred forty-nine".