163491973 has 2 divisors, whose sum is σ = 163491974. Its totient is φ = 163491972.

The previous prime is 163491967. The next prime is 163491997. The reversal of 163491973 is 379194361.

163491973 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 161366209 + 2125764 = 12703^2 + 1458^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-163491973 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (163491943) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 81745986 + 81745987.

It is an arithmetic number, because the mean of its divisors is an integer number (81745987).

Almost surely, 2^163491973 is an apocalyptic number.

It is an amenable number.

163491973 is a deficient number, since it is larger than the sum of its proper divisors (1).

163491973 is an equidigital number, since it uses as much as digits as its factorization.

163491973 is an evil number, because the sum of its binary digits is even.

The product of its digits is 122472, while the sum is 43.

The square root of 163491973 is about 12786.3979681535. The cubic root of 163491973 is about 546.8045817923.

The spelling of 163491973 in words is "one hundred sixty-three million, four hundred ninety-one thousand, nine hundred seventy-three".