971721 has 12 divisors (see below), whose sum is σ = 1418820. Its totient is φ = 640800.

The previous prime is 971713. The next prime is 971723. The reversal of 971721 is 127179.

It can be written as a sum of positive squares in 2 ways, for example, as 741321 + 230400 = 861^2 + 480^2 .

It is not a de Polignac number, because 971721 - 2³ = 971713 is a prime.

It is a Curzon number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 971721.

It is not an unprimeable number, because it can be changed into a prime (971723) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 375 + ... + 1443.

It is an arithmetic number, because the mean of its divisors is an integer number (118235).

2⁹⁷¹⁷²¹ is an apocalyptic number.

It is an amenable number.

971721 is a deficient number, since it is larger than the sum of its proper divisors (447099).

971721 is a wasteful number, since it uses less digits than its factorization.

971721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1176 (or 1173 counting only the distinct ones).

The product of its digits is 882, while the sum is 27.

The square root of 971721 is about 985.7590983602. The cubic root of 971721 is about 99.0483388057.

The spelling of 971721 in words is "nine hundred seventy-one thousand, seven hundred twenty-one".