9721988 has 12 divisors (see below), whose sum is σ = 17043852. Its totient is φ = 4852320.

The previous prime is 9721979. The next prime is 9721991. The reversal of 9721988 is 8891279.

It can be written as a sum of positive squares in 2 ways, for example, as 7739524 + 1982464 = 2782^2 + 1408^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 806 + ... + 4482.

It is an arithmetic number, because the mean of its divisors is an integer number (1420321).

Almost surely, 2^9721988 is an apocalyptic number.

It is an amenable number.

9721988 is a deficient number, since it is larger than the sum of its proper divisors (7321864).

9721988 is a wasteful number, since it uses less digits than its factorization.

9721988 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4342 (or 4340 counting only the distinct ones).

The product of its digits is 72576, while the sum is 44.

The square root of 9721988 is about 3118.0102629722. The cubic root of 9721988 is about 213.4281468741.

The spelling of 9721988 in words is "nine million, seven hundred twenty-one thousand, nine hundred eighty-eight".