16991669 has 4 divisors (see below), whose sum is σ = 17245344. Its totient is φ = 16737996.

The previous prime is 16991659. The next prime is 16991701. The reversal of 16991669 is 96619961.

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: 96619961 = 307 ⋅314723.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-16991669 is a prime.

It is a super-2 number, since 2×16991669² = 577433630811122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16991629) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 126737 + ... + 126870.

It is an arithmetic number, because the mean of its divisors is an integer number (4311336).

Almost surely, 2^16991669 is an apocalyptic number.

It is an amenable number.

16991669 is a deficient number, since it is larger than the sum of its proper divisors (253675).

16991669 is an equidigital number, since it uses as much as digits as its factorization.

16991669 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 253674.

The product of its digits is 157464, while the sum is 47.

The square root of 16991669 is about 4122.0952196668. The cubic root of 16991669 is about 257.0861495617.

The spelling of 16991669 in words is "sixteen million, nine hundred ninety-one thousand, six hundred sixty-nine".