72043681 has 2 divisors, whose sum is σ = 72043682. Its totient is φ = 72043680.

The previous prime is 72043669. The next prime is 72043691. The reversal of 72043681 is 18634027.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 61701025 + 10342656 = 7855^2 + 3216^2 .

It is a cyclic number.

It is not a de Polignac number, because 72043681 - 2¹³ = 72035489 is a prime.

It is a super-2 number, since 2×72043681² = 10380583944059522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (72043691) 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, 36021840 + 36021841.

It is an arithmetic number, because the mean of its divisors is an integer number (36021841).

Almost surely, 2^72043681 is an apocalyptic number.

It is an amenable number.

72043681 is a deficient number, since it is larger than the sum of its proper divisors (1).

72043681 is an equidigital number, since it uses as much as digits as its factorization.

72043681 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8064, while the sum is 31.

The square root of 72043681 is about 8487.8549115781. The cubic root of 72043681 is about 416.1008773634.

The spelling of 72043681 in words is "seventy-two million, forty-three thousand, six hundred eighty-one".