16257991 has 4 divisors (see below), whose sum is σ = 16305192. Its totient is φ = 16210792.

The previous prime is 16257973. The next prime is 16258007. The reversal of 16257991 is 19975261.

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

It is a cyclic number.

It is not a de Polignac number, because 16257991 - 2⁵ = 16257959 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16257931) 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, 23080 + ... + 23773.

It is an arithmetic number, because the mean of its divisors is an integer number (4076298).

Almost surely, 2^16257991 is an apocalyptic number.

16257991 is a deficient number, since it is larger than the sum of its proper divisors (47201).

16257991 is an equidigital number, since it uses as much as digits as its factorization.

16257991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 47200.

The product of its digits is 34020, while the sum is 40.

The square root of 16257991 is about 4032.1199138915. The cubic root of 16257991 is about 253.3313629040.

The spelling of 16257991 in words is "sixteen million, two hundred fifty-seven thousand, nine hundred ninety-one".