16404257 has 4 divisors (see below), whose sum is σ = 16447920. Its totient is φ = 16360596.

The previous prime is 16404253. The next prime is 16404281. The reversal of 16404257 is 75240461.

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, and also an emirpimes, since its reverse is a distinct semiprime: 75240461 = 877 ⋅85793.

It is a cyclic number.

It is not a de Polignac number, because 16404257 - 2² = 16404253 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16404251) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21263 + ... + 22020.

It is an arithmetic number, because the mean of its divisors is an integer number (4111980).

Almost surely, 2^16404257 is an apocalyptic number.

It is an amenable number.

16404257 is a deficient number, since it is larger than the sum of its proper divisors (43663).

16404257 is an equidigital number, since it uses as much as digits as its factorization.

16404257 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43662.

The product of its (nonzero) digits is 6720, while the sum is 29.

The square root of 16404257 is about 4050.2169077717. The cubic root of 16404257 is about 254.0887996293.

It can be divided in two parts, 16404 and 257, that added together give a palindrome (16661).

The spelling of 16404257 in words is "sixteen million, four hundred four thousand, two hundred fifty-seven".