18661745 has 4 divisors (see below), whose sum is σ = 22394100. Its totient is φ = 14929392.

The previous prime is 18661739. The next prime is 18661751. The reversal of 18661745 is 54716681.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 54716681 = 3673 ⋅14897.

It is an interprime number because it is at equal distance from previous prime (18661739) and next prime (18661751).

It can be written as a sum of positive squares in 2 ways, for example, as 3389281 + 15272464 = 1841^2 + 3908^2 .

It is a cyclic number.

It is not a de Polignac number, because 18661745 - 2⁶ = 18661681 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 18661699 and 18661708.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1866170 + ... + 1866179.

It is an arithmetic number, because the mean of its divisors is an integer number (5598525).

Almost surely, 2^18661745 is an apocalyptic number.

It is an amenable number.

18661745 is a deficient number, since it is larger than the sum of its proper divisors (3732355).

18661745 is an equidigital number, since it uses as much as digits as its factorization.

18661745 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3732354.

The product of its digits is 40320, while the sum is 38.

The square root of 18661745 is about 4319.9241891496. The cubic root of 18661745 is about 265.2471646757.

The spelling of 18661745 in words is "eighteen million, six hundred sixty-one thousand, seven hundred forty-five".