72770238721 has 4 divisors (see below), whose sum is σ = 73437855700. Its totient is φ = 72102621744.

The previous prime is 72770238647. The next prime is 72770238757. The reversal of 72770238721 is 12783207727.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 39347086321 + 33423152400 = 198361^2 + 182820^2 .

It is a cyclic number.

It is not a de Polignac number, because 72770238721 - 2¹¹ = 72770236673 is a prime.

It is a super-2 number, since 2×72770238721² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (72770238781) 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, 333808326 + ... + 333808543.

It is an arithmetic number, because the mean of its divisors is an integer number (18359463925).

Almost surely, 2^72770238721 is an apocalyptic number.

It is an amenable number.

72770238721 is a deficient number, since it is larger than the sum of its proper divisors (667616979).

72770238721 is a wasteful number, since it uses less digits than its factorization.

72770238721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 667616978.

The product of its (nonzero) digits is 460992, while the sum is 46.

The spelling of 72770238721 in words is "seventy-two billion, seven hundred seventy million, two hundred thirty-eight thousand, seven hundred twenty-one".