678161591 has 2 divisors, whose sum is σ = 678161592. Its totient is φ = 678161590.

The previous prime is 678161573. The next prime is 678161633. The reversal of 678161591 is 195161876.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 678161591 - 2⁶ = 678161527 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (678161531) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 339080795 + 339080796.

It is an arithmetic number, because the mean of its divisors is an integer number (339080796).

Almost surely, 2^678161591 is an apocalyptic number.

678161591 is a deficient number, since it is larger than the sum of its proper divisors (1).

678161591 is an equidigital number, since it uses as much as digits as its factorization.

678161591 is an evil number, because the sum of its binary digits is even.

The product of its digits is 90720, while the sum is 44.

The square root of 678161591 is about 26041.5358802049. The cubic root of 678161591 is about 878.5727514316.

The spelling of 678161591 in words is "six hundred seventy-eight million, one hundred sixty-one thousand, five hundred ninety-one".