72726723521 has 4 divisors (see below), whose sum is σ = 72844595652. Its totient is φ = 72608851392.

The previous prime is 72726723473. The next prime is 72726723527. The reversal of 72726723521 is 12532762727.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12532762727 = 91099 ⋅137573.

It can be written as a sum of positive squares in 2 ways, for example, as 24968740225 + 47757983296 = 158015^2 + 218536^2 .

It is a cyclic number.

It is not a de Polignac number, because 72726723521 - 2⁶ = 72726723457 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (72726723527) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 58935140 + ... + 58936373.

It is an arithmetic number, because the mean of its divisors is an integer number (18211148913).

Almost surely, 2^72726723521 is an apocalyptic number.

It is an amenable number.

72726723521 is a deficient number, since it is larger than the sum of its proper divisors (117872131).

72726723521 is a wasteful number, since it uses less digits than its factorization.

72726723521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 117872130.

The product of its digits is 493920, while the sum is 44.

The spelling of 72726723521 in words is "seventy-two billion, seven hundred twenty-six million, seven hundred twenty-three thousand, five hundred twenty-one".