840318722721 has 9 divisors (see below), whose sum is σ = 1213797682929. Its totient is φ = 560210648436.

The previous prime is 840318722693. The next prime is 840318722753. The reversal of 840318722721 is 127227813048.

The square root of 840318722721 is 916689.

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

840318722721 is a `hidden beast` number, since 8 + 403 + 18 + 7 + 227 + 2 + 1 = 666.

It is a tau number, because it is divible by the number of its divisors (9).

It is not a de Polignac number, because 840318722721 - 2⁹ = 840318722209 is a prime.

It is a super-2 number, since 2×840318722721² (a number of 25 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (840318762721) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 2597286 + ... + 2902848.

Almost surely, 2^840318722721 is an apocalyptic number.

840318722721 is the 916689-th square number.

840318722721 is the 458345-th centered octagonal number.

It is an amenable number.

840318722721 is a deficient number, since it is larger than the sum of its proper divisors (373478960208).

840318722721 is an frugal number, since it uses more digits than its factorization.

840318722721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 611132 (or 305566 counting only the distinct ones).

The product of its (nonzero) digits is 301056, while the sum is 45.

The spelling of 840318722721 in words is "eight hundred forty billion, three hundred eighteen million, seven hundred twenty-two thousand, seven hundred twenty-one".