721661884611 has 16 divisors (see below), whose sum is σ = 963874141728. Its totient is φ = 480278937600.

The previous prime is 721661884549. The next prime is 721661884633. The reversal of 721661884611 is 116488166127.

It is not a de Polignac number, because 721661884611 - 2¹¹ = 721661882563 is a prime.

It is not an unprimeable number, because it can be changed into a prime (721661884651) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 31309251 + ... + 31332291.

It is an arithmetic number, because the mean of its divisors is an integer number (60242133858).

Almost surely, 2^721661884611 is an apocalyptic number.

721661884611 is a deficient number, since it is larger than the sum of its proper divisors (242212257117).

721661884611 is a wasteful number, since it uses less digits than its factorization.

721661884611 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40582.

The product of its digits is 774144, while the sum is 51.

The spelling of 721661884611 in words is "seven hundred twenty-one billion, six hundred sixty-one million, eight hundred eighty-four thousand, six hundred eleven".