721327122161 has 8 divisors (see below), whose sum is σ = 725679525600. Its totient is φ = 716978304000.

The previous prime is 721327122151. The next prime is 721327122169. The reversal of 721327122161 is 161221723127.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 721327122161 - 2⁶ = 721327122097 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (721327122169) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 492176 + ... + 1298033.

It is an arithmetic number, because the mean of its divisors is an integer number (90709940700).

Almost surely, 2^721327122161 is an apocalyptic number.

It is an amenable number.

721327122161 is a deficient number, since it is larger than the sum of its proper divisors (4352403439).

721327122161 is a wasteful number, since it uses less digits than its factorization.

721327122161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1792639.

The product of its digits is 14112, while the sum is 35.

Adding to 721327122161 its reverse (161221723127), we get a palindrome (882548845288).

The spelling of 721327122161 in words is "seven hundred twenty-one billion, three hundred twenty-seven million, one hundred twenty-two thousand, one hundred sixty-one".