72917681 has 2 divisors, whose sum is σ = 72917682. Its totient is φ = 72917680.

The previous prime is 72917671. The next prime is 72917707. The reversal of 72917681 is 18671927.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 58599025 + 14318656 = 7655^2 + 3784^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-72917681 is a prime.

It is a super-2 number, since 2×72917681² = 10633976404835522, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (72917671) 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, 36458840 + 36458841.

It is an arithmetic number, because the mean of its divisors is an integer number (36458841).

Almost surely, 2^72917681 is an apocalyptic number.

It is an amenable number.

72917681 is a deficient number, since it is larger than the sum of its proper divisors (1).

72917681 is an equidigital number, since it uses as much as digits as its factorization.

72917681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 42336, while the sum is 41.

The square root of 72917681 is about 8539.1850313716. The cubic root of 72917681 is about 417.7767651067.

The spelling of 72917681 in words is "seventy-two million, nine hundred seventeen thousand, six hundred eighty-one".