971721306 has 64 divisors (see below), whose sum is σ = 2230824960. Its totient is φ = 313295040.

The previous prime is 971721221. The next prime is 971721307. The reversal of 971721306 is 603127179.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (971721307) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 360295 + ... + 362981.

It is an arithmetic number, because the mean of its divisors is an integer number (34856640).

Almost surely, 2^971721306 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 971721306, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1115412480).

971721306 is an abundant number, since it is smaller than the sum of its proper divisors (1259103654).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

971721306 is a wasteful number, since it uses less digits than its factorization.

971721306 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2916 (or 2910 counting only the distinct ones).

The product of its (nonzero) digits is 15876, while the sum is 36.

The square root of 971721306 is about 31172.4446587046. Note that the first 3 decimals coincide. The cubic root of 971721306 is about 990.4834920268.

The spelling of 971721306 in words is "nine hundred seventy-one million, seven hundred twenty-one thousand, three hundred six".