9772720861 has 16 divisors (see below), whose sum is σ = 10809293184. Its totient is φ = 8788324864.

The previous prime is 9772720849. The next prime is 9772720877. The reversal of 9772720861 is 1680272779.

It is a cyclic number.

It is not a de Polignac number, because 9772720861 - 2⁷ = 9772720733 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 (9772720361) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 357081 + ... + 383473.

It is an arithmetic number, because the mean of its divisors is an integer number (675580824).

Almost surely, 2^9772720861 is an apocalyptic number.

It is an amenable number.

9772720861 is a deficient number, since it is larger than the sum of its proper divisors (1036572323).

9772720861 is a wasteful number, since it uses less digits than its factorization.

9772720861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27380.

The product of its (nonzero) digits is 592704, while the sum is 49.

The square root of 9772720861 is about 98857.0728931420. The cubic root of 9772720861 is about 2137.9875147414.

The spelling of 9772720861 in words is "nine billion, seven hundred seventy-two million, seven hundred twenty thousand, eight hundred sixty-one".