72209866081 has 2 divisors, whose sum is σ = 72209866082. Its totient is φ = 72209866080.

The previous prime is 72209866033. The next prime is 72209866093. The reversal of 72209866081 is 18066890227.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 50933267856 + 21276598225 = 225684^2 + 145865^2 .

It is a cyclic number.

It is not a de Polignac number, because 72209866081 - 2²³ = 72201477473 is a prime.

It is a super-2 number, since 2×72209866081² (a number of 23 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (72209846081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36104933040 + 36104933041.

It is an arithmetic number, because the mean of its divisors is an integer number (36104933041).

Almost surely, 2^72209866081 is an apocalyptic number.

It is an amenable number.

72209866081 is a deficient number, since it is larger than the sum of its proper divisors (1).

72209866081 is an equidigital number, since it uses as much as digits as its factorization.

72209866081 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 580608, while the sum is 49.

The spelling of 72209866081 in words is "seventy-two billion, two hundred nine million, eight hundred sixty-six thousand, eighty-one".