9720000021 has 8 divisors (see below), whose sum is σ = 12989932480. Its totient is φ = 6465033792.

The previous prime is 9720000013. The next prime is 9720000041. The reversal of 9720000021 is 1200000279.

It is a happy number.

9720000021 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is not a de Polignac number, because 9720000021 - 2³ = 9720000013 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 (9720000041) 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 7 ways as a sum of consecutive naturals, for example, 3740041 + ... + 3742638.

It is an arithmetic number, because the mean of its divisors is an integer number (1623741560).

Almost surely, 2^9720000021 is an apocalyptic number.

It is an amenable number.

9720000021 is a deficient number, since it is larger than the sum of its proper divisors (3269932459).

9720000021 is a wasteful number, since it uses less digits than its factorization.

9720000021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7483115.

The product of its (nonzero) digits is 252, while the sum is 21.

The square root of 9720000021 is about 98590.0604574315. The cubic root of 9720000021 is about 2134.1359842310.

The spelling of 9720000021 in words is "nine billion, seven hundred twenty million, twenty-one", and thus it is an aban number.