16497561 has 4 divisors (see below), whose sum is σ = 21996752. Its totient is φ = 10998372.

The previous prime is 16497557. The next prime is 16497577. The reversal of 16497561 is 16579461.

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: 16579461 = 3 ⋅5526487.

It is not a de Polignac number, because 16497561 - 2² = 16497557 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 16.

It is not an unprimeable number, because it can be changed into a prime (16497461) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2749591 + ... + 2749596.

It is an arithmetic number, because the mean of its divisors is an integer number (5499188).

Almost surely, 2^16497561 is an apocalyptic number.

It is an amenable number.

16497561 is a deficient number, since it is larger than the sum of its proper divisors (5499191).

16497561 is an equidigital number, since it uses as much as digits as its factorization.

16497561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5499190.

The product of its digits is 45360, while the sum is 39.

The square root of 16497561 is about 4061.7189710762. The cubic root of 16497561 is about 254.5696239071.

The spelling of 16497561 in words is "sixteen million, four hundred ninety-seven thousand, five hundred sixty-one".