18811649 has 2 divisors, whose sum is σ = 18811650. Its totient is φ = 18811648.

The previous prime is 18811643. The next prime is 18811679. The reversal of 18811649 is 94611881.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16056049 + 2755600 = 4007^2 + 1660^2 .

It is a cyclic number.

It is not a de Polignac number, because 18811649 - 2⁸ = 18811393 is a prime.

It is not a weakly prime, because it can be changed into another prime (18811643) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9405824 + 9405825.

It is an arithmetic number, because the mean of its divisors is an integer number (9405825).

Almost surely, 2^18811649 is an apocalyptic number.

It is an amenable number.

18811649 is a deficient number, since it is larger than the sum of its proper divisors (1).

18811649 is an equidigital number, since it uses as much as digits as its factorization.

18811649 is an evil number, because the sum of its binary digits is even.

The product of its digits is 13824, while the sum is 38.

The square root of 18811649 is about 4337.2397904658. The cubic root of 18811649 is about 265.9554874920.

The spelling of 18811649 in words is "eighteen million, eight hundred eleven thousand, six hundred forty-nine".