18440693 has 4 divisors (see below), whose sum is σ = 18890508. Its totient is φ = 17990880.

The previous prime is 18440677. The next prime is 18440707. The reversal of 18440693 is 39604481.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 4765489 + 13675204 = 2183^2 + 3698^2 .

It is a cyclic number.

It is not a de Polignac number, because 18440693 - 2⁴ = 18440677 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18440623) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 224846 + ... + 224927.

It is an arithmetic number, because the mean of its divisors is an integer number (4722627).

Almost surely, 2^18440693 is an apocalyptic number.

It is an amenable number.

18440693 is a deficient number, since it is larger than the sum of its proper divisors (449815).

18440693 is an equidigital number, since it uses as much as digits as its factorization.

18440693 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 449814.

The product of its (nonzero) digits is 20736, while the sum is 35.

The square root of 18440693 is about 4294.2628005282. The cubic root of 18440693 is about 264.1957006614.

The spelling of 18440693 in words is "eighteen million, four hundred forty thousand, six hundred ninety-three".