18687397 has 8 divisors (see below), whose sum is σ = 19404000. Its totient is φ = 17975664.

The previous prime is 18687391. The next prime is 18687401. The reversal of 18687397 is 79378681.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 18687397 - 2⁷ = 18687269 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 18687397.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18687391) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7854 + ... + 9952.

It is an arithmetic number, because the mean of its divisors is an integer number (2425500).

Almost surely, 2^18687397 is an apocalyptic number.

It is an amenable number.

18687397 is a deficient number, since it is larger than the sum of its proper divisors (716603).

18687397 is a wasteful number, since it uses less digits than its factorization.

18687397 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2435.

The product of its digits is 508032, while the sum is 49.

The square root of 18687397 is about 4322.8922031436. The cubic root of 18687397 is about 265.3686432236.

The spelling of 18687397 in words is "eighteen million, six hundred eighty-seven thousand, three hundred ninety-seven".