681322751 has 2 divisors, whose sum is σ = 681322752. Its totient is φ = 681322750.

The previous prime is 681322739. The next prime is 681322823. The reversal of 681322751 is 157223186.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 681322751 - 2²² = 677128447 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 (681322351) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 340661375 + 340661376.

It is an arithmetic number, because the mean of its divisors is an integer number (340661376).

Almost surely, 2^681322751 is an apocalyptic number.

681322751 is a deficient number, since it is larger than the sum of its proper divisors (1).

681322751 is an equidigital number, since it uses as much as digits as its factorization.

681322751 is an evil number, because the sum of its binary digits is even.

The product of its digits is 20160, while the sum is 35.

The square root of 681322751 is about 26102.1598914726. The cubic root of 681322751 is about 879.9357524548.

The spelling of 681322751 in words is "six hundred eighty-one million, three hundred twenty-two thousand, seven hundred fifty-one".