72981281 has 2 divisors, whose sum is σ = 72981282. Its totient is φ = 72981280.

The previous prime is 72981269. The next prime is 72981283. The reversal of 72981281 is 18218927.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 47831056 + 25150225 = 6916^2 + 5015^2 .

It is a cyclic number.

It is not a de Polignac number, because 72981281 - 2²⁶ = 5872417 is a prime.

It is a super-2 number, since 2×72981281² = 10652534752801922, which contains 22 as substring.

Together with 72981283, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (72981283) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36490640 + 36490641.

It is an arithmetic number, because the mean of its divisors is an integer number (36490641).

Almost surely, 2^72981281 is an apocalyptic number.

It is an amenable number.

72981281 is a deficient number, since it is larger than the sum of its proper divisors (1).

72981281 is an equidigital number, since it uses as much as digits as its factorization.

72981281 is an evil number, because the sum of its binary digits is even.

The product of its digits is 16128, while the sum is 38.

The square root of 72981281 is about 8542.9082284665. The cubic root of 72981281 is about 417.8981937302.

The spelling of 72981281 in words is "seventy-two million, nine hundred eighty-one thousand, two hundred eighty-one".