18661288 has 8 divisors (see below), whose sum is σ = 34989930. Its totient is φ = 9330640.

The previous prime is 18661277. The next prime is 18661289. The reversal of 18661288 is 88216681.

It can be written as a sum of positive squares in only one way, i.e., 17455684 + 1205604 = 4178^2 + 1098^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is a self number, because there is not a number n which added to its sum of digits gives 18661288.

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 as a sum of consecutive naturals, namely, 1166323 + ... + 1166338.

Almost surely, 2^18661288 is an apocalyptic number.

It is an amenable number.

18661288 is a deficient number, since it is larger than the sum of its proper divisors (16328642).

18661288 is a wasteful number, since it uses less digits than its factorization.

18661288 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2332667 (or 2332663 counting only the distinct ones).

The product of its digits is 36864, while the sum is 40.

The square root of 18661288 is about 4319.8712943790. The cubic root of 18661288 is about 265.2449994808.

The spelling of 18661288 in words is "eighteen million, six hundred sixty-one thousand, two hundred eighty-eight".