18397644 has 12 divisors (see below), whose sum is σ = 42927864. Its totient is φ = 6132544.

The previous prime is 18397637. The next prime is 18397649. The reversal of 18397644 is 44679381.

It is a tau number, because it is divible by the number of its divisors (12).

It is a junction number, because it is equal to n+sod(n) for n = 18397596 and 18397605.

It is not an unprimeable number, because it can be changed into a prime (18397649) 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, 766557 + ... + 766580.

It is an arithmetic number, because the mean of its divisors is an integer number (3577322).

Almost surely, 2^18397644 is an apocalyptic number.

It is an amenable number.

18397644 is an abundant number, since it is smaller than the sum of its proper divisors (24530220).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18397644 is a wasteful number, since it uses less digits than its factorization.

18397644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1533144 (or 1533142 counting only the distinct ones).

The product of its digits is 145152, while the sum is 42.

The square root of 18397644 is about 4289.2474864479. The cubic root of 18397644 is about 263.9899559999.

The spelling of 18397644 in words is "eighteen million, three hundred ninety-seven thousand, six hundred forty-four".