18987264 has 144 divisors (see below), whose sum is σ = 58376640. Its totient is φ = 6082560.

The previous prime is 18987263. The next prime is 18987299. The reversal of 18987264 is 46278981.

It is a tau number, because it is divible by the number of its divisors (144).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18987263) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 283359 + ... + 283425.

Almost surely, 2^18987264 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18987264, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29188320).

18987264 is an abundant number, since it is smaller than the sum of its proper divisors (39389376).

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

18987264 is an equidigital number, since it uses as much as digits as its factorization.

18987264 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 133 (or 113 counting only the distinct ones).

The product of its digits is 193536, while the sum is 45.

The square root of 18987264 is about 4357.4377792460. The cubic root of 18987264 is about 266.7805291534.

The spelling of 18987264 in words is "eighteen million, nine hundred eighty-seven thousand, two hundred sixty-four".