9912392721 has 81 divisors (see below), whose sum is σ = 18349878729. Its totient is φ = 5137347600.

The previous prime is 9912392713. The next prime is 9912392729. The reversal of 9912392721 is 1272932199.

The square root of 9912392721 is 99561.

It is a perfect power (a square), and thus also a powerful number.

It is an interprime number because it is at equal distance from previous prime (9912392713) and next prime (9912392729).

It is not a de Polignac number, because 9912392721 - 2³ = 9912392713 is a prime.

It is not an unprimeable number, because it can be changed into a prime (9912392729) by changing a digit.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 22998376 + ... + 22998806.

Almost surely, 2^9912392721 is an apocalyptic number.

9912392721 is the 99561-st square number.

9912392721 is the 49781-st centered octagonal number.

It is an amenable number.

9912392721 is a deficient number, since it is larger than the sum of its proper divisors (8437486008).

9912392721 is a wasteful number, since it uses less digits than its factorization.

9912392721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 904 (or 452 counting only the distinct ones).

The product of its digits is 122472, while the sum is 45.

The cubic root of 9912392721 is about 2148.1247554280.

It can be divided in two parts, 99123 and 92721, that added together give a square (191844 = 438²).

The spelling of 9912392721 in words is "nine billion, nine hundred twelve million, three hundred ninety-two thousand, seven hundred twenty-one".