18640905 has 32 divisors (see below), whose sum is σ = 30841344. Its totient is φ = 9609216.

The previous prime is 18640903. The next prime is 18640913. The reversal of 18640905 is 50904681.

It is not a de Polignac number, because 18640905 - 2¹ = 18640903 is a prime.

It is not an unprimeable number, because it can be changed into a prime (18640903) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 96489 + ... + 96681.

It is an arithmetic number, because the mean of its divisors is an integer number (963792).

Almost surely, 2^18640905 is an apocalyptic number.

18640905 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

18640905 is a deficient number, since it is larger than the sum of its proper divisors (12200439).

18640905 is a wasteful number, since it uses less digits than its factorization.

18640905 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 385.

The product of its (nonzero) digits is 8640, while the sum is 33.

The square root of 18640905 is about 4317.5114360011. The cubic root of 18640905 is about 265.1483920288.

The spelling of 18640905 in words is "eighteen million, six hundred forty thousand, nine hundred five".