16491217 has 4 divisors (see below), whose sum is σ = 16525296. Its totient is φ = 16457140.

The previous prime is 16491203. The next prime is 16491257. The reversal of 16491217 is 71219461.

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: 71219461 = 71 ⋅1003091.

It is a cyclic number.

It is not a de Polignac number, because 16491217 - 2⁷ = 16491089 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16491257) 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, 16303 + ... + 17284.

It is an arithmetic number, because the mean of its divisors is an integer number (4131324).

Almost surely, 2^16491217 is an apocalyptic number.

It is an amenable number.

16491217 is a deficient number, since it is larger than the sum of its proper divisors (34079).

16491217 is an equidigital number, since it uses as much as digits as its factorization.

16491217 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34078.

The product of its digits is 3024, while the sum is 31.

The square root of 16491217 is about 4060.9379458445. The cubic root of 16491217 is about 254.5369888457.

The spelling of 16491217 in words is "sixteen million, four hundred ninety-one thousand, two hundred seventeen".