9945831021 has 16 divisors (see below), whose sum is σ = 15194524800. Its totient is φ = 5668717248.

The previous prime is 9945831001. The next prime is 9945831089. The reversal of 9945831021 is 1201385499.

It is not a de Polignac number, because 9945831021 - 2¹⁷ = 9945699949 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9945831001) 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, 600586 + ... + 616923.

It is an arithmetic number, because the mean of its divisors is an integer number (949657800).

Almost surely, 2^9945831021 is an apocalyptic number.

It is an amenable number.

9945831021 is a deficient number, since it is larger than the sum of its proper divisors (5248693779).

9945831021 is a wasteful number, since it uses less digits than its factorization.

9945831021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1217908.

The product of its (nonzero) digits is 77760, while the sum is 42.

The square root of 9945831021 is about 99728.7873234203. The cubic root of 9945831021 is about 2150.5375271110.

The spelling of 9945831021 in words is "nine billion, nine hundred forty-five million, eight hundred thirty-one thousand, twenty-one".