9129145823821 has 4 divisors (see below), whose sum is σ = 9130898400700. Its totient is φ = 9127393246944.

The previous prime is 9129145823801. The next prime is 9129145823827. The reversal of 9129145823821 is 1283285419219.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 6632097981796 + 2497047842025 = 2575286^2 + 1580205^2 .

It is a cyclic number.

It is not a de Polignac number, because 9129145823821 - 2¹¹ = 9129145821773 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 (9129145823827) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 876280626 + ... + 876291043.

It is an arithmetic number, because the mean of its divisors is an integer number (2282724600175).

Almost surely, 2^{9129145823821} is an apocalyptic number.

It is an amenable number.

9129145823821 is a deficient number, since it is larger than the sum of its proper divisors (1752576879).

9129145823821 is a wasteful number, since it uses less digits than its factorization.

9129145823821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1752576878.

The product of its digits is 2488320, while the sum is 55.

The spelling of 9129145823821 in words is "nine trillion, one hundred twenty-nine billion, one hundred forty-five million, eight hundred twenty-three thousand, eight hundred twenty-one".