971688681 has 6 divisors (see below), whose sum is σ = 1403550330. Its totient is φ = 647792448.

The previous prime is 971688649. The next prime is 971688779. The reversal of 971688681 is 186886179.

It can be written as a sum of positive squares in only one way, i.e., 785120400 + 186568281 = 28020^2 + 13659^2 .

It is not a de Polignac number, because 971688681 - 2⁵ = 971688649 is a prime.

It is a super-2 number, since 2×971688681² = 1888357785567039522, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (971688611) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 53982696 + ... + 53982713.

It is an arithmetic number, because the mean of its divisors is an integer number (233925055).

Almost surely, 2^971688681 is an apocalyptic number.

It is an amenable number.

971688681 is a deficient number, since it is larger than the sum of its proper divisors (431861649).

971688681 is a wasteful number, since it uses less digits than its factorization.

971688681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 107965415 (or 107965412 counting only the distinct ones).

The product of its digits is 1161216, while the sum is 54.

The square root of 971688681 is about 31171.9213556046. The cubic root of 971688681 is about 990.4724069261.

The spelling of 971688681 in words is "nine hundred seventy-one million, six hundred eighty-eight thousand, six hundred eighty-one".