9721591975 has 6 divisors (see below), whose sum is σ = 12054774080. Its totient is φ = 7777273560.

The previous prime is 9721591951. The next prime is 9721591981. The reversal of 9721591975 is 5791951279.

It is a happy number.

It is not a de Polignac number, because 9721591975 - 2¹⁵ = 9721559207 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 194431815 + ... + 194431864.

Almost surely, 2^9721591975 is an apocalyptic number.

9721591975 is a deficient number, since it is larger than the sum of its proper divisors (2333182105).

9721591975 is a wasteful number, since it uses less digits than its factorization.

9721591975 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 388863689 (or 388863684 counting only the distinct ones).

The product of its digits is 1786050, while the sum is 55.

The square root of 9721591975 is about 98598.1337298024. The cubic root of 9721591975 is about 2134.2524883752.

The spelling of 9721591975 in words is "nine billion, seven hundred twenty-one million, five hundred ninety-one thousand, nine hundred seventy-five".