681813953 has 2 divisors, whose sum is σ = 681813954. Its totient is φ = 681813952.

The previous prime is 681813931. The next prime is 681813961. The reversal of 681813953 is 359318186.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 654950464 + 26863489 = 25592^2 + 5183^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-681813953 is a prime.

It is not a weakly prime, because it can be changed into another prime (681813053) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 340906976 + 340906977.

It is an arithmetic number, because the mean of its divisors is an integer number (340906977).

Almost surely, 2^681813953 is an apocalyptic number.

It is an amenable number.

681813953 is a deficient number, since it is larger than the sum of its proper divisors (1).

681813953 is an equidigital number, since it uses as much as digits as its factorization.

681813953 is an evil number, because the sum of its binary digits is even.

The product of its digits is 155520, while the sum is 44.

The square root of 681813953 is about 26111.5674175259. The cubic root of 681813953 is about 880.1471659006.

The spelling of 681813953 in words is "six hundred eighty-one million, eight hundred thirteen thousand, nine hundred fifty-three".