16638997 has 4 divisors (see below), whose sum is σ = 16687296. Its totient is φ = 16590700.

The previous prime is 16638991. The next prime is 16639001. The reversal of 16638997 is 79983661.

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 a de Polignac number, because none of the positive numbers 2^k-16638997 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 16638997.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16638991) 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, 23629 + ... + 24322.

It is an arithmetic number, because the mean of its divisors is an integer number (4171824).

Almost surely, 2^16638997 is an apocalyptic number.

It is an amenable number.

16638997 is a deficient number, since it is larger than the sum of its proper divisors (48299).

16638997 is an equidigital number, since it uses as much as digits as its factorization.

16638997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48298.

The product of its digits is 489888, while the sum is 49.

The square root of 16638997 is about 4079.0926687194. The cubic root of 16638997 is about 255.2950423226.

The spelling of 16638997 in words is "sixteen million, six hundred thirty-eight thousand, nine hundred ninety-seven".