72029081581 has 2 divisors, whose sum is σ = 72029081582. Its totient is φ = 72029081580.

The previous prime is 72029081519. The next prime is 72029081611. The reversal of 72029081581 is 18518092027.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 44714908681 + 27314172900 = 211459^2 + 165270^2 .

It is a cyclic number.

It is not a de Polignac number, because 72029081581 - 2¹¹ = 72029079533 is a prime.

It is a super-2 number, since 2×72029081581² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (72029081381) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36014540790 + 36014540791.

It is an arithmetic number, because the mean of its divisors is an integer number (36014540791).

Almost surely, 2^72029081581 is an apocalyptic number.

It is an amenable number.

72029081581 is a deficient number, since it is larger than the sum of its proper divisors (1).

72029081581 is an equidigital number, since it uses as much as digits as its factorization.

72029081581 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 80640, while the sum is 43.

The spelling of 72029081581 in words is "seventy-two billion, twenty-nine million, eighty-one thousand, five hundred eighty-one".