731642440321 has 27 divisors (see below), whose sum is σ = 836385464259. Its totient is φ = 639632112912.

The previous prime is 731642440279. The next prime is 731642440409. The reversal of 731642440321 is 123044246137.

The square root of 731642440321 is 855361.

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

It can be written as a sum of positive squares in only one way, i.e., 108231130225 + 623411310096 = 328985^2 + 789564^2 .

It is not a de Polignac number, because 731642440321 - 2²⁷ = 731508222593 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (731642447321) 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 26 ways as a sum of consecutive naturals, for example, 211272436 + ... + 211275898.

It is an arithmetic number, because the mean of its divisors is an integer number (30977239417).

Almost surely, 2^731642440321 is an apocalyptic number.

731642440321 is the 855361-st square number.

731642440321 is the 427681-st centered octagonal number.

It is an amenable number.

731642440321 is a deficient number, since it is larger than the sum of its proper divisors (104743023938).

731642440321 is an frugal number, since it uses more digits than its factorization.

731642440321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6990 (or 3495 counting only the distinct ones).

The product of its (nonzero) digits is 96768, while the sum is 37.

Adding to 731642440321 its reverse (123044246137), we get a palindrome (854686686458).

The spelling of 731642440321 in words is "seven hundred thirty-one billion, six hundred forty-two million, four hundred forty thousand, three hundred twenty-one".