72280781 has 2 divisors, whose sum is σ = 72280782. Its totient is φ = 72280780.

The previous prime is 72280757. The next prime is 72280829. The reversal of 72280781 is 18708227.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 37576900 + 34703881 = 6130^2 + 5891^2 .

It is a cyclic number.

It is not a de Polignac number, because 72280781 - 2⁶ = 72280717 is a prime.

It is a super-2 number, since 2×72280781² = 10449022603939922, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (72280081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36140390 + 36140391.

It is an arithmetic number, because the mean of its divisors is an integer number (36140391).

Almost surely, 2^72280781 is an apocalyptic number.

It is an amenable number.

72280781 is a deficient number, since it is larger than the sum of its proper divisors (1).

72280781 is an equidigital number, since it uses as much as digits as its factorization.

72280781 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12544, while the sum is 35.

The square root of 72280781 is about 8501.8104542503. The cubic root of 72280781 is about 416.5568483562.

The spelling of 72280781 in words is "seventy-two million, two hundred eighty thousand, seven hundred eighty-one".