971001981 has 24 divisors (see below), whose sum is σ = 1435946616. Its totient is φ = 632102400.

The previous prime is 971001979. The next prime is 971002007. The reversal of 971001981 is 189100179.

971001981 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 118069956 + 852932025 = 10866^2 + 29205^2 .

It is not a de Polignac number, because 971001981 - 2¹ = 971001979 is a prime.

It is a super-2 number, since 2×971001981² = 1885689694211848722, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (971001901) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 59041 + ... + 73673.

It is an arithmetic number, because the mean of its divisors is an integer number (59831109).

Almost surely, 2^971001981 is an apocalyptic number.

It is an amenable number.

971001981 is a deficient number, since it is larger than the sum of its proper divisors (464944635).

971001981 is a wasteful number, since it uses less digits than its factorization.

971001981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14813 (or 14810 counting only the distinct ones).

The product of its (nonzero) digits is 4536, while the sum is 36.

The square root of 971001981 is about 31160.9046884072. The cubic root of 971001981 is about 990.2390270716.

The spelling of 971001981 in words is "nine hundred seventy-one million, one thousand, nine hundred eighty-one".