18989478 has 48 divisors (see below), whose sum is σ = 43754256. Its totient is φ = 6168960.

The previous prime is 18989471. The next prime is 18989479. The reversal of 18989478 is 87498981.

18989478 is nontrivially palindromic in base 12.

It is a Harshad number since it is a multiple of its sum of digits (54).

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18989471) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 19450 + ... + 20402.

It is an arithmetic number, because the mean of its divisors is an integer number (911547).

Almost surely, 2^18989478 is an apocalyptic number.

18989478 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 18989478, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21877128).

18989478 is an abundant number, since it is smaller than the sum of its proper divisors (24764778).

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

18989478 is an equidigital number, since it uses as much as digits as its factorization.

18989478 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1011 (or 999 counting only the distinct ones).

The product of its digits is 1161216, while the sum is 54.

The square root of 18989478 is about 4357.6918202186. The cubic root of 18989478 is about 266.7908980184.

The spelling of 18989478 in words is "eighteen million, nine hundred eighty-nine thousand, four hundred seventy-eight".