19691669 has 2 divisors, whose sum is σ = 19691670. Its totient is φ = 19691668.

The previous prime is 19691641. The next prime is 19691671. The reversal of 19691669 is 96619691.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11356900 + 8334769 = 3370^2 + 2887^2 .

It is a cyclic number.

It is not a de Polignac number, because 19691669 - 2¹⁶ = 19626133 is a prime.

It is a super-2 number, since 2×19691669² = 775523656011122, which contains 22 as substring.

Together with 19691671, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19691629) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9845834 + 9845835.

It is an arithmetic number, because the mean of its divisors is an integer number (9845835).

Almost surely, 2^19691669 is an apocalyptic number.

It is an amenable number.

19691669 is a deficient number, since it is larger than the sum of its proper divisors (1).

19691669 is an equidigital number, since it uses as much as digits as its factorization.

19691669 is an evil number, because the sum of its binary digits is even.

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

The square root of 19691669 is about 4437.5296055350. The cubic root of 19691669 is about 270.0396329566.

The spelling of 19691669 in words is "nineteen million, six hundred ninety-one thousand, six hundred sixty-nine".