72181328 has 10 divisors (see below), whose sum is σ = 139851354. Its totient is φ = 36090656.

The previous prime is 72181321. The next prime is 72181357. The reversal of 72181328 is 82318127.

It can be written as a sum of positive squares in only one way, i.e., 45265984 + 26915344 = 6728^2 + 5188^2 .

It is a super-2 number, since 2×72181328² = 10420288223687168, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 72181294 and 72181303.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72181321) 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, 2255651 + ... + 2255682.

Almost surely, 2^72181328 is an apocalyptic number.

It is an amenable number.

72181328 is a deficient number, since it is larger than the sum of its proper divisors (67670026).

72181328 is a wasteful number, since it uses less digits than its factorization.

72181328 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4511341 (or 4511335 counting only the distinct ones).

The product of its digits is 5376, while the sum is 32.

The square root of 72181328 is about 8495.9595102613. The cubic root of 72181328 is about 416.3657102106.

The spelling of 72181328 in words is "seventy-two million, one hundred eighty-one thousand, three hundred twenty-eight".