163989691 has 2 divisors, whose sum is σ = 163989692. Its totient is φ = 163989690.

The previous prime is 163989677. The next prime is 163989697. The reversal of 163989691 is 196989361.

163989691 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-163989691 is a prime.

It is not a weakly prime, because it can be changed into another prime (163989697) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 81994845 + 81994846.

It is an arithmetic number, because the mean of its divisors is an integer number (81994846).

Almost surely, 2^163989691 is an apocalyptic number.

163989691 is a deficient number, since it is larger than the sum of its proper divisors (1).

163989691 is an equidigital number, since it uses as much as digits as its factorization.

163989691 is an evil number, because the sum of its binary digits is even.

The product of its digits is 629856, while the sum is 52.

The square root of 163989691 is about 12805.8459697124. The cubic root of 163989691 is about 547.3588980503.

The spelling of 163989691 in words is "one hundred sixty-three million, nine hundred eighty-nine thousand, six hundred ninety-one".