18631409 has 2 divisors, whose sum is σ = 18631410. Its totient is φ = 18631408.

The previous prime is 18631399. The next prime is 18631423. The reversal of 18631409 is 90413681.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18515809 + 115600 = 4303^2 + 340^2 .

It is a cyclic number.

It is not a de Polignac number, because 18631409 - 2¹⁶ = 18565873 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (18631429) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9315704 + 9315705.

It is an arithmetic number, because the mean of its divisors is an integer number (9315705).

Almost surely, 2^18631409 is an apocalyptic number.

It is an amenable number.

18631409 is a deficient number, since it is larger than the sum of its proper divisors (1).

18631409 is an equidigital number, since it uses as much as digits as its factorization.

18631409 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5184, while the sum is 32.

The square root of 18631409 is about 4316.4115883451. The cubic root of 18631409 is about 265.1033606530.

The spelling of 18631409 in words is "eighteen million, six hundred thirty-one thousand, four hundred nine".