18445890 has 16 divisors (see below), whose sum is σ = 44270208. Its totient is φ = 4918896.

The previous prime is 18445883. The next prime is 18445897. The reversal of 18445890 is 9854481.

It is an interprime number because it is at equal distance from previous prime (18445883) and next prime (18445897).

It is not an unprimeable number, because it can be changed into a prime (18445897) by changing a digit.

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 in 7 ways as a sum of consecutive naturals, for example, 307402 + ... + 307461.

It is an arithmetic number, because the mean of its divisors is an integer number (2766888).

Almost surely, 2^18445890 is an apocalyptic number.

18445890 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

18445890 is an abundant number, since it is smaller than the sum of its proper divisors (25824318).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18445890 is a wasteful number, since it uses less digits than its factorization.

18445890 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 614873.

The product of its (nonzero) digits is 46080, while the sum is 39.

The square root of 18445890 is about 4294.8678675834. The cubic root of 18445890 is about 264.2205170841.

The spelling of 18445890 in words is "eighteen million, four hundred forty-five thousand, eight hundred ninety".