18661284 has 36 divisors (see below), whose sum is σ = 47378604. Its totient is φ = 6193152.

The previous prime is 18661277. The next prime is 18661289. The reversal of 18661284 is 48216681.

It can be written as a sum of positive squares in 2 ways, for example, as 17388900 + 1272384 = 4170^2 + 1128^2 .

It is a tau number, because it is divible by the number of its divisors (36).

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

It is not an unprimeable number, because it can be changed into a prime (18661289) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8244 + ... + 10260.

Almost surely, 2^18661284 is an apocalyptic number.

It is an amenable number.

18661284 is an abundant number, since it is smaller than the sum of its proper divisors (28717320).

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

18661284 is a wasteful number, since it uses less digits than its factorization.

18661284 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2284 (or 2279 counting only the distinct ones).

The product of its digits is 18432, while the sum is 36.

The square root of 18661284 is about 4319.8708314023. The cubic root of 18661284 is about 265.2449805293.

The spelling of 18661284 in words is "eighteen million, six hundred sixty-one thousand, two hundred eighty-four".