16566397 has 4 divisors (see below), whose sum is σ = 16579420. Its totient is φ = 16553376.

The previous prime is 16566383. The next prime is 16566409. The reversal of 16566397 is 79366561.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 8608356 + 7958041 = 2934^2 + 2821^2 .

It is a cyclic number.

It is not a de Polignac number, because 16566397 - 2²³ = 8177789 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 (16566367) 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, 4368 + ... + 7225.

It is an arithmetic number, because the mean of its divisors is an integer number (4144855).

Almost surely, 2^16566397 is an apocalyptic number.

It is an amenable number.

16566397 is a deficient number, since it is larger than the sum of its proper divisors (13023).

16566397 is a wasteful number, since it uses less digits than its factorization.

16566397 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13022.

The product of its digits is 204120, while the sum is 43.

The square root of 16566397 is about 4070.1839024791. The cubic root of 16566397 is about 254.9231961443.

The spelling of 16566397 in words is "sixteen million, five hundred sixty-six thousand, three hundred ninety-seven".