72487324781 has 2 divisors, whose sum is σ = 72487324782. Its totient is φ = 72487324780.

The previous prime is 72487324729. The next prime is 72487324817. The reversal of 72487324781 is 18742378427.

Together with next prime (72487324817) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 71913003556 + 574321225 = 268166^2 + 23965^2 .

It is a cyclic number.

It is not a de Polignac number, because 72487324781 - 2²² = 72483130477 is a prime.

It is a super-2 number, since 2×72487324781² (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 (72487324181) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36243662390 + 36243662391.

It is an arithmetic number, because the mean of its divisors is an integer number (36243662391).

Almost surely, 2^72487324781 is an apocalyptic number.

It is an amenable number.

72487324781 is a deficient number, since it is larger than the sum of its proper divisors (1).

72487324781 is an equidigital number, since it uses as much as digits as its factorization.

72487324781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4214784, while the sum is 53.

The spelling of 72487324781 in words is "seventy-two billion, four hundred eighty-seven million, three hundred twenty-four thousand, seven hundred eighty-one".