9126978745921 has 3 divisors (see below), whose sum is σ = 9126981767011. Its totient is φ = 9126975724832.

The previous prime is 9126978745889. The next prime is 9126978745933. The reversal of 9126978745921 is 1295478796219.

The square root of 9126978745921 is 3021089.

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

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 32170368321 + 9094808377600 = 179361^2 + 3015760^2 .

It is not a de Polignac number, because 9126978745921 - 2⁵ = 9126978745889 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (9126978745981) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 1510545 + ... + 4531633.

Almost surely, 2^{9126978745921} is an apocalyptic number.

9126978745921 is the 3021089-th square number.

9126978745921 is the 1510545-th centered octagonal number.

It is an amenable number.

9126978745921 is a deficient number, since it is larger than the sum of its proper divisors (3021090).

9126978745921 is an frugal number, since it uses more digits than its factorization.

9126978745921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6042178 (or 3021089 counting only the distinct ones).

The product of its digits is 137168640, while the sum is 70.

The spelling of 9126978745921 in words is "nine trillion, one hundred twenty-six billion, nine hundred seventy-eight million, seven hundred forty-five thousand, nine hundred twenty-one".