16691657 has 2 divisors, whose sum is σ = 16691658. Its totient is φ = 16691656.

The previous prime is 16691651. The next prime is 16691659. The reversal of 16691657 is 75619661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16516096 + 175561 = 4064^2 + 419^2 .

It is a cyclic number.

It is not a de Polignac number, because 16691657 - 2⁶ = 16691593 is a prime.

It is a super-2 number, since 2×16691657² = 557222826811298, which contains 22 as substring.

Together with 16691659, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (16691651) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8345828 + 8345829.

It is an arithmetic number, because the mean of its divisors is an integer number (8345829).

Almost surely, 2^16691657 is an apocalyptic number.

It is an amenable number.

16691657 is a deficient number, since it is larger than the sum of its proper divisors (1).

16691657 is an equidigital number, since it uses as much as digits as its factorization.

16691657 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 68040, while the sum is 41.

The square root of 16691657 is about 4085.5424364459. The cubic root of 16691657 is about 255.5640825622.

The spelling of 16691657 in words is "sixteen million, six hundred ninety-one thousand, six hundred fifty-seven".