72081581 has 32 divisors (see below), whose sum is σ = 90720000. Its totient is φ = 56263680.

The previous prime is 72081557. The next prime is 72081589. The reversal of 72081581 is 18518027.

It is a happy number.

It is not a de Polignac number, because 72081581 - 2¹⁴ = 72065197 is a prime.

It is a super-2 number, since 2×72081581² = 10391508638919122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72081589) 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 31 ways as a sum of consecutive naturals, for example, 362120 + ... + 362318.

It is an arithmetic number, because the mean of its divisors is an integer number (2835000).

Almost surely, 2^72081581 is an apocalyptic number.

It is an amenable number.

72081581 is a deficient number, since it is larger than the sum of its proper divisors (18638419).

72081581 is a wasteful number, since it uses less digits than its factorization.

72081581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 389.

The product of its (nonzero) digits is 4480, while the sum is 32.

The square root of 72081581 is about 8490.0872198111. The cubic root of 72081581 is about 416.1738305979.

The spelling of 72081581 in words is "seventy-two million, eighty-one thousand, five hundred eighty-one".