840336921 has 24 divisors (see below), whose sum is σ = 1283493120. Its totient is φ = 528335136.

The previous prime is 840336919. The next prime is 840336929. The reversal of 840336921 is 129633048.

It is not a de Polignac number, because 840336921 - 2¹ = 840336919 is a prime.

It is a super-2 number, since 2×840336921² = 1412332281591520482, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (840336929) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 27115 + ... + 49151.

It is an arithmetic number, because the mean of its divisors is an integer number (53478880).

Almost surely, 2^840336921 is an apocalyptic number.

It is an amenable number.

840336921 is a deficient number, since it is larger than the sum of its proper divisors (443156199).

840336921 is a wasteful number, since it uses less digits than its factorization.

840336921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22285 (or 22282 counting only the distinct ones).

The product of its (nonzero) digits is 31104, while the sum is 36.

The square root of 840336921 is about 28988.5653491165. The cubic root of 840336921 is about 943.6649292147.

Adding to 840336921 its reverse (129633048), we get a palindrome (969969969).

The spelling of 840336921 in words is "eight hundred forty million, three hundred thirty-six thousand, nine hundred twenty-one".