18990432 has 72 divisors (see below), whose sum is σ = 54427464. Its totient is φ = 6280704.

The previous prime is 18990427. The next prime is 18990451. The reversal of 18990432 is 23409981.

It is a tau number, because it is divible by the number of its divisors (72).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 66963 + ... + 67245.

It is an arithmetic number, because the mean of its divisors is an integer number (755937).

Almost surely, 2^18990432 is an apocalyptic number.

18990432 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18990432, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27213732).

18990432 is an abundant number, since it is smaller than the sum of its proper divisors (35437032).

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

18990432 is a wasteful number, since it uses less digits than its factorization.

18990432 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 532 (or 521 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 36.

The square root of 18990432 is about 4357.8012804624. The cubic root of 18990432 is about 266.7953656549.

The spelling of 18990432 in words is "eighteen million, nine hundred ninety thousand, four hundred thirty-two".