72881381 has 2 divisors, whose sum is σ = 72881382. Its totient is φ = 72881380.

The previous prime is 72881357. The next prime is 72881399. The reversal of 72881381 is 18318827.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 56761156 + 16120225 = 7534^2 + 4015^2 .

It is an emirp because it is prime and its reverse (18318827) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 72881381 - 2⁶ = 72881317 is a prime.

It is a super-2 number, since 2×72881381² = 10623391392934322, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (72881351) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36440690 + 36440691.

It is an arithmetic number, because the mean of its divisors is an integer number (36440691).

Almost surely, 2^72881381 is an apocalyptic number.

It is an amenable number.

72881381 is a deficient number, since it is larger than the sum of its proper divisors (1).

72881381 is an equidigital number, since it uses as much as digits as its factorization.

72881381 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 21504, while the sum is 38.

The square root of 72881381 is about 8537.0592712011. The cubic root of 72881381 is about 417.7074274939.

The spelling of 72881381 in words is "seventy-two million, eight hundred eighty-one thousand, three hundred eighty-one".