9721663 has 8 divisors (see below), whose sum is σ = 11593728. Its totient is φ = 7970424.

The previous prime is 9721643. The next prime is 9721667. The reversal of 9721663 is 3661279.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 9721663 - 2¹³ = 9713471 is a prime.

It is a Duffinian number.

9721663 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9721667) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 30031 + ... + 30352.

It is an arithmetic number, because the mean of its divisors is an integer number (1449216).

Almost surely, 2^9721663 is an apocalyptic number.

9721663 is a deficient number, since it is larger than the sum of its proper divisors (1872065).

9721663 is a wasteful number, since it uses less digits than its factorization.

9721663 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60413.

The product of its digits is 13608, while the sum is 34.

The square root of 9721663 is about 3117.9581459667. The cubic root of 9721663 is about 213.4257685909.

It can be divided in two parts, 97216 and 63, that added together give a palindrome (97279).

The spelling of 9721663 in words is "nine million, seven hundred twenty-one thousand, six hundred sixty-three".