18690388 has 6 divisors (see below), whose sum is σ = 32708186. Its totient is φ = 9345192.

The previous prime is 18690377. The next prime is 18690391. The reversal of 18690388 is 88309681.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 18507204 + 183184 = 4302^2 + 428^2 .

It is a congruent number.

It is an unprimeable number.

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, 2336295 + ... + 2336302.

Almost surely, 2^18690388 is an apocalyptic number.

It is an amenable number.

18690388 is a deficient number, since it is larger than the sum of its proper divisors (14017798).

18690388 is a wasteful number, since it uses less digits than its factorization.

18690388 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4672601 (or 4672599 counting only the distinct ones).

The product of its (nonzero) digits is 82944, while the sum is 43.

The square root of 18690388 is about 4323.2381382478. The cubic root of 18690388 is about 265.3828002741.

The spelling of 18690388 in words is "eighteen million, six hundred ninety thousand, three hundred eighty-eight".