72031081 has 4 divisors (see below), whose sum is σ = 73390212. Its totient is φ = 70671952.

The previous prime is 72031067. The next prime is 72031087. The reversal of 72031081 is 18013027.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18013027 = 79 ⋅228013.

It can be written as a sum of positive squares in 2 ways, for example, as 32592681 + 39438400 = 5709^2 + 6280^2 .

It is a cyclic number.

It is not a de Polignac number, because 72031081 - 2⁵ = 72031049 is a prime.

It is a super-2 number, since 2×72031081² = 10376953260057122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (72031087) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 679486 + ... + 679591.

It is an arithmetic number, because the mean of its divisors is an integer number (18347553).

Almost surely, 2^72031081 is an apocalyptic number.

It is an amenable number.

72031081 is a deficient number, since it is larger than the sum of its proper divisors (1359131).

72031081 is a wasteful number, since it uses less digits than its factorization.

72031081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1359130.

The product of its (nonzero) digits is 336, while the sum is 22.

The square root of 72031081 is about 8487.1126421180. The cubic root of 72031081 is about 416.0766181147.

The spelling of 72031081 in words is "seventy-two million, thirty-one thousand, eighty-one".