18431906 has 4 divisors (see below), whose sum is σ = 27647862. Its totient is φ = 9215952.

The previous prime is 18431879. The next prime is 18431923. The reversal of 18431906 is 60913481.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 60913481 = 31 ⋅1964951.

It can be written as a sum of positive squares in only one way, i.e., 14371681 + 4060225 = 3791^2 + 2015^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4607975 + ... + 4607978.

Almost surely, 2^18431906 is an apocalyptic number.

18431906 is a deficient number, since it is larger than the sum of its proper divisors (9215956).

18431906 is an equidigital number, since it uses as much as digits as its factorization.

18431906 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9215955.

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

The square root of 18431906 is about 4293.2395693695. The cubic root of 18431906 is about 264.1537308640.

The spelling of 18431906 in words is "eighteen million, four hundred thirty-one thousand, nine hundred six".