18989490 has 128 divisors (see below), whose sum is σ = 53706240. Its totient is φ = 4257792.

The previous prime is 18989489. The next prime is 18989491. The reversal of 18989490 is 9498981.

It is an interprime number because it is at equal distance from previous prime (18989489) and next prime (18989491).

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

It is not an unprimeable number, because it can be changed into a prime (18989491) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 260094 + ... + 260166.

It is an arithmetic number, because the mean of its divisors is an integer number (419580).

Almost surely, 2^18989490 is an apocalyptic number.

18989490 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 18989490, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26853120).

18989490 is an abundant number, since it is smaller than the sum of its proper divisors (34716750).

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

18989490 is a wasteful number, since it uses less digits than its factorization.

18989490 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 148.

The product of its (nonzero) digits is 186624, while the sum is 48.

The square root of 18989490 is about 4357.6931970941. The cubic root of 18989490 is about 266.7909542160.

The spelling of 18989490 in words is "eighteen million, nine hundred eighty-nine thousand, four hundred ninety".