72321805 has 8 divisors (see below), whose sum is σ = 86890392. Its totient is φ = 57787968.

The previous prime is 72321803. The next prime is 72321811. The reversal of 72321805 is 50812327.

It can be written as a sum of positive squares in 4 ways, for example, as 2866249 + 69455556 = 1693^2 + 8334^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 72321805 - 2¹ = 72321803 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72321803) 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 7 ways as a sum of consecutive naturals, for example, 3862 + ... + 12631.

It is an arithmetic number, because the mean of its divisors is an integer number (10861299).

Almost surely, 2^72321805 is an apocalyptic number.

It is an amenable number.

72321805 is a deficient number, since it is larger than the sum of its proper divisors (14568587).

72321805 is a wasteful number, since it uses less digits than its factorization.

72321805 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17375.

The product of its (nonzero) digits is 3360, while the sum is 28.

The square root of 72321805 is about 8504.2227745985. Note that the first 3 decimals coincide. The cubic root of 72321805 is about 416.6356410676.

The spelling of 72321805 in words is "seventy-two million, three hundred twenty-one thousand, eight hundred five".