72781013 has 2 divisors, whose sum is σ = 72781014. Its totient is φ = 72781012.

The previous prime is 72781003. The next prime is 72781021. The reversal of 72781013 is 31018727.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 41499364 + 31281649 = 6442^2 + 5593^2 .

It is a cyclic number.

It is not a de Polignac number, because 72781013 - 2⁶ = 72780949 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (72781003) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36390506 + 36390507.

It is an arithmetic number, because the mean of its divisors is an integer number (36390507).

Almost surely, 2^72781013 is an apocalyptic number.

It is an amenable number.

72781013 is a deficient number, since it is larger than the sum of its proper divisors (1).

72781013 is an equidigital number, since it uses as much as digits as its factorization.

72781013 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2352, while the sum is 29.

The square root of 72781013 is about 8531.1788751614. The cubic root of 72781013 is about 417.5155919452.

The spelling of 72781013 in words is "seventy-two million, seven hundred eighty-one thousand, thirteen".