18443897 has 4 divisors (see below), whose sum is σ = 18496500. Its totient is φ = 18391296.

The previous prime is 18443879. The next prime is 18443923. The reversal of 18443897 is 79834481.

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 2611456 + 15832441 = 1616^2 + 3979^2 .

It is a cyclic number.

It is not a de Polignac number, because 18443897 - 2⁶ = 18443833 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18443837) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 25772 + ... + 26477.

It is an arithmetic number, because the mean of its divisors is an integer number (4624125).

Almost surely, 2^18443897 is an apocalyptic number.

It is an amenable number.

18443897 is a deficient number, since it is larger than the sum of its proper divisors (52603).

18443897 is an equidigital number, since it uses as much as digits as its factorization.

18443897 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52602.

The product of its digits is 193536, while the sum is 44.

The square root of 18443897 is about 4294.6358402081. The cubic root of 18443897 is about 264.2110007734.

The spelling of 18443897 in words is "eighteen million, four hundred forty-three thousand, eight hundred ninety-seven".