971979521 has 4 divisors (see below), whose sum is σ = 979399344. Its totient is φ = 964559700.

The previous prime is 971979493. The next prime is 971979559. The reversal of 971979521 is 125979179.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 971979521 - 2¹⁸ = 971717377 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 971979521.

It is not an unprimeable number, because it can be changed into a prime (971979721) 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 3 ways as a sum of consecutive naturals, for example, 3709715 + ... + 3709976.

It is an arithmetic number, because the mean of its divisors is an integer number (244849836).

Almost surely, 2^971979521 is an apocalyptic number.

It is an amenable number.

971979521 is a deficient number, since it is larger than the sum of its proper divisors (7419823).

971979521 is a wasteful number, since it uses less digits than its factorization.

971979521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7419822.

The product of its digits is 357210, while the sum is 50.

The square root of 971979521 is about 31176.5861023942. The cubic root of 971979521 is about 990.5712178121.

The spelling of 971979521 in words is "nine hundred seventy-one million, nine hundred seventy-nine thousand, five hundred twenty-one".