18910649 has 2 divisors, whose sum is σ = 18910650. Its totient is φ = 18910648.

The previous prime is 18910609. The next prime is 18910657. The reversal of 18910649 is 94601981.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12996025 + 5914624 = 3605^2 + 2432^2 .

It is an emirp because it is prime and its reverse (94601981) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18910649 - 2¹² = 18906553 is a prime.

It is a super-2 number, since 2×18910649² = 715225291202402, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (18910609) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9455324 + 9455325.

It is an arithmetic number, because the mean of its divisors is an integer number (9455325).

Almost surely, 2^18910649 is an apocalyptic number.

It is an amenable number.

18910649 is a deficient number, since it is larger than the sum of its proper divisors (1).

18910649 is an equidigital number, since it uses as much as digits as its factorization.

18910649 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 15552, while the sum is 38.

The square root of 18910649 is about 4348.6376027441. The cubic root of 18910649 is about 266.4212191177.

The spelling of 18910649 in words is "eighteen million, nine hundred ten thousand, six hundred forty-nine".