72005681 has 16 divisors (see below), whose sum is σ = 80352000. Its totient is φ = 63974400.

The previous prime is 72005603. The next prime is 72005683. The reversal of 72005681 is 18650027.

It is a cyclic number.

It is not a de Polignac number, because 72005681 - 2¹⁰ = 72004657 is a prime.

It is a super-2 number, since 2×72005681² = 10369636192547522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (72005683) 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 in 15 ways as a sum of consecutive naturals, for example, 160145 + ... + 160593.

It is an arithmetic number, because the mean of its divisors is an integer number (5022000).

Almost surely, 2^72005681 is an apocalyptic number.

It is an amenable number.

72005681 is a deficient number, since it is larger than the sum of its proper divisors (8346319).

72005681 is a wasteful number, since it uses less digits than its factorization.

72005681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 760.

The product of its (nonzero) digits is 3360, while the sum is 29.

The square root of 72005681 is about 8485.6161237709. The cubic root of 72005681 is about 416.0277059487.

The spelling of 72005681 in words is "seventy-two million, five thousand, six hundred eighty-one".