685631951 has 2 divisors, whose sum is σ = 685631952. Its totient is φ = 685631950.

The previous prime is 685631939. The next prime is 685631957. The reversal of 685631951 is 159136586.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-685631951 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 (685631957) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 342815975 + 342815976.

It is an arithmetic number, because the mean of its divisors is an integer number (342815976).

Almost surely, 2^685631951 is an apocalyptic number.

685631951 is a deficient number, since it is larger than the sum of its proper divisors (1).

685631951 is an equidigital number, since it uses as much as digits as its factorization.

685631951 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 194400, while the sum is 44.

The square root of 685631951 is about 26184.5746767061. The cubic root of 685631951 is about 881.7869813085.

The spelling of 685631951 in words is "six hundred eighty-five million, six hundred thirty-one thousand, nine hundred fifty-one".