18513890 has 16 divisors (see below), whose sum is σ = 34474680. Its totient is φ = 7150080.

The previous prime is 18513883. The next prime is 18513917. The reversal of 18513890 is 9831581.

It can be written as a sum of positive squares in 4 ways, for example, as 16008001 + 2505889 = 4001^2 + 1583^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 18513890.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 31631 + ... + 32210.

Almost surely, 2^18513890 is an apocalyptic number.

18513890 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

18513890 is a deficient number, since it is larger than the sum of its proper divisors (15960790).

18513890 is a wasteful number, since it uses less digits than its factorization.

18513890 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 63877.

The product of its (nonzero) digits is 8640, while the sum is 35.

The square root of 18513890 is about 4302.7770102574. Note that the first 3 decimals coincide. The cubic root of 18513890 is about 264.5447982126.

The spelling of 18513890 in words is "eighteen million, five hundred thirteen thousand, eight hundred ninety".