9721661279 has 16 divisors (see below), whose sum is σ = 10852669440. Its totient is φ = 8632606560.

The previous prime is 9721661269. The next prime is 9721661333.

9721661279 is nontrivially palindromic in base 10.

9721661279 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 9721661279 - 2²⁰ = 9720612703 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9721661219) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 244682 + ... + 281624.

It is an arithmetic number, because the mean of its divisors is an integer number (678291840).

Almost surely, 2^9721661279 is an apocalyptic number.

9721661279 is a deficient number, since it is larger than the sum of its proper divisors (1131008161).

9721661279 is a wasteful number, since it uses less digits than its factorization.

9721661279 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37510.

The product of its digits is 571536, while the sum is 50.

The square root of 9721661279 is about 98598.4851759904. The cubic root of 9721661279 is about 2134.2575599686.

The spelling of 9721661279 in words is "nine billion, seven hundred twenty-one million, six hundred sixty-one thousand, two hundred seventy-nine".