840084066721 has 3 divisors (see below), whose sum is σ = 840084983283. Its totient is φ = 840083150160.

The previous prime is 840084066683. The next prime is 840084066737. The reversal of 840084066721 is 127660480048.

The square root of 840084066721 is 916561.

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., 14457417121 + 825626649600 = 120239^2 + 908640^2 .

It is not a de Polignac number, because 840084066721 - 2⁷ = 840084066593 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (840084066781) 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, 458281 + ... + 1374841.

It is an arithmetic number, because the mean of its divisors is an integer number (280028327761).

Almost surely, 2^840084066721 is an apocalyptic number.

840084066721 is the 916561-st square number.

840084066721 is the 458281-st centered octagonal number.

It is an amenable number.

840084066721 is a deficient number, since it is larger than the sum of its proper divisors (916562).

840084066721 is an frugal number, since it uses more digits than its factorization.

840084066721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1833122 (or 916561 counting only the distinct ones).

The product of its (nonzero) digits is 516096, while the sum is 46.

The spelling of 840084066721 in words is "eight hundred forty billion, eighty-four million, sixty-six thousand, seven hundred twenty-one".