16691643 has 16 divisors (see below), whose sum is σ = 25100160. Its totient is φ = 10960488.

The previous prime is 16691621. The next prime is 16691651. The reversal of 16691643 is 34619661.

16691643 is a `hidden beast` number, since 1 + 6 + 6 + 9 + 1 + 643 = 666.

It is not a de Polignac number, because 16691643 - 2⁶ = 16691579 is a prime.

It is a super-2 number, since 2×16691643² = 557221892078898, which contains 22 as substring.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 16691598 and 16691607.

It is not an unprimeable number, because it can be changed into a prime (16691693) 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 15 ways as a sum of consecutive naturals, for example, 2805 + ... + 6422.

It is an arithmetic number, because the mean of its divisors is an integer number (1568760).

Almost surely, 2^16691643 is an apocalyptic number.

16691643 is a deficient number, since it is larger than the sum of its proper divisors (8408517).

16691643 is an equidigital number, since it uses as much as digits as its factorization.

16691643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9303 (or 9297 counting only the distinct ones).

The product of its digits is 23328, while the sum is 36.

The square root of 16691643 is about 4085.5407230867. The cubic root of 16691643 is about 255.5640111114.

It can be divided in two parts, 166 and 91643, that added together give a square (91809 = 303²).

The spelling of 16691643 in words is "sixteen million, six hundred ninety-one thousand, six hundred forty-three".