18661490 has 16 divisors (see below), whose sum is σ = 33716952. Its totient is φ = 7436544.

The previous prime is 18661483. The next prime is 18661499. The reversal of 18661490 is 9416681.

It can be written as a sum of positive squares in 4 ways, for example, as 12061729 + 6599761 = 3473^2 + 2569^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 18661490.

It is not an unprimeable number, because it can be changed into a prime (18661499) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 599 + ... + 6138.

Almost surely, 2^18661490 is an apocalyptic number.

18661490 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

18661490 is a deficient number, since it is larger than the sum of its proper divisors (15055462).

18661490 is a wasteful number, since it uses less digits than its factorization.

18661490 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7021.

The product of its (nonzero) digits is 10368, while the sum is 35.

The square root of 18661490 is about 4319.8946746420. The cubic root of 18661490 is about 265.2459565297.

The spelling of 18661490 in words is "eighteen million, six hundred sixty-one thousand, four hundred ninety".