18409897 has 4 divisors (see below), whose sum is σ = 20083536. Its totient is φ = 16736260.

The previous prime is 18409883. The next prime is 18409907. The reversal of 18409897 is 79890481.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 18409897 - 2¹⁵ = 18377129 is a prime.

It is not an unprimeable number, because it can be changed into a prime (18409817) 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, 836803 + ... + 836824.

It is an arithmetic number, because the mean of its divisors is an integer number (5020884).

Almost surely, 2^18409897 is an apocalyptic number.

It is an amenable number.

18409897 is a deficient number, since it is larger than the sum of its proper divisors (1673639).

18409897 is a wasteful number, since it uses less digits than its factorization.

18409897 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1673638.

The product of its (nonzero) digits is 145152, while the sum is 46.

The square root of 18409897 is about 4290.6755878300. The cubic root of 18409897 is about 264.0485495729.

It can be divided in two parts, 18409 and 897, that added together give a triangular number (19306 = T₁₉₆).

The spelling of 18409897 in words is "eighteen million, four hundred nine thousand, eight hundred ninety-seven".