72189581 has 2 divisors, whose sum is σ = 72189582. Its totient is φ = 72189580.

The previous prime is 72189577. The next prime is 72189587. The reversal of 72189581 is 18598127.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 54834025 + 17355556 = 7405^2 + 4166^2 .

It is a cyclic number.

It is not a de Polignac number, because 72189581 - 2² = 72189577 is a prime.

It is a super-2 number, since 2×72189581² = 10422671209911122, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (72189587) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36094790 + 36094791.

It is an arithmetic number, because the mean of its divisors is an integer number (36094791).

Almost surely, 2^72189581 is an apocalyptic number.

It is an amenable number.

72189581 is a deficient number, since it is larger than the sum of its proper divisors (1).

72189581 is an equidigital number, since it uses as much as digits as its factorization.

72189581 is an evil number, because the sum of its binary digits is even.

The product of its digits is 40320, while the sum is 41.

The square root of 72189581 is about 8496.4451978460. The cubic root of 72189581 is about 416.3815782813.

The spelling of 72189581 in words is "seventy-two million, one hundred eighty-nine thousand, five hundred eighty-one".