18649997 has 4 divisors (see below), whose sum is σ = 18670176. Its totient is φ = 18629820.

The previous prime is 18649979. The next prime is 18650041. The reversal of 18649997 is 79994681.

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 18649997 - 2²⁰ = 17601421 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 (18649907) 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, 8633 + ... + 10574.

It is an arithmetic number, because the mean of its divisors is an integer number (4667544).

Almost surely, 2^18649997 is an apocalyptic number.

It is an amenable number.

18649997 is a deficient number, since it is larger than the sum of its proper divisors (20179).

18649997 is an equidigital number, since it uses as much as digits as its factorization.

18649997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20178.

The product of its digits is 979776, while the sum is 53.

The square root of 18649997 is about 4318.5642290002. The cubic root of 18649997 is about 265.1914932507.

The spelling of 18649997 in words is "eighteen million, six hundred forty-nine thousand, nine hundred ninety-seven".