857940921 has 12 divisors (see below), whose sum is σ = 1312145172. Its totient is φ = 538315776.

The previous prime is 857940911. The next prime is 857940971. The reversal of 857940921 is 129049758.

857940921 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 648415296 + 209525625 = 25464^2 + 14475^2 .

It is not a de Polignac number, because 857940921 - 2¹⁰ = 857939897 is a prime.

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (857940911) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2803576 + ... + 2803881.

It is an arithmetic number, because the mean of its divisors is an integer number (109345431).

Almost surely, 2^857940921 is an apocalyptic number.

It is an amenable number.

857940921 is a deficient number, since it is larger than the sum of its proper divisors (454204251).

857940921 is a wasteful number, since it uses less digits than its factorization.

857940921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5607480 (or 5607477 counting only the distinct ones).

The product of its (nonzero) digits is 181440, while the sum is 45.

The square root of 857940921 is about 29290.6285524910. The cubic root of 857940921 is about 950.2089737881.

The spelling of 857940921 in words is "eight hundred fifty-seven million, nine hundred forty thousand, nine hundred twenty-one".