18945890 has 16 divisors (see below), whose sum is σ = 34217208. Its totient is φ = 7552896.

The previous prime is 18945877. The next prime is 18945893. The reversal of 18945890 is 9854981.

It can be written as a sum of positive squares in 4 ways, for example, as 4330561 + 14615329 = 2081^2 + 3823^2 .

It is an alternating number because its digits alternate between odd and even.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (18945893) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 104 + ... + 6156.

Almost surely, 2^18945890 is an apocalyptic number.

18945890 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

18945890 is a deficient number, since it is larger than the sum of its proper divisors (15271318).

18945890 is a wasteful number, since it uses less digits than its factorization.

18945890 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6373.

The product of its (nonzero) digits is 103680, while the sum is 44.

The square root of 18945890 is about 4352.6876754484. The cubic root of 18945890 is about 266.5866131230.

Subtracting from 18945890 its reverse (9854981), we obtain a palindrome (9090909).

The spelling of 18945890 in words is "eighteen million, nine hundred forty-five thousand, eight hundred ninety".