721320233 has 6 divisors (see below), whose sum is σ = 736996266. Its totient is φ = 705970832.

The previous prime is 721320221. The next prime is 721320241. The reversal of 721320233 is 332023127.

It can be written as a sum of positive squares in only one way, i.e., 646532329 + 74787904 = 25427^2 + 8648^2 .

It is not a de Polignac number, because 721320233 - 2¹⁶ = 721254697 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 721320199 and 721320208.

It is not an unprimeable number, because it can be changed into a prime (721320263) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 161060 + ... + 165477.

It is an arithmetic number, because the mean of its divisors is an integer number (122832711).

Almost surely, 2^721320233 is an apocalyptic number.

It is an amenable number.

721320233 is a deficient number, since it is larger than the sum of its proper divisors (15676033).

721320233 is an equidigital number, since it uses as much as digits as its factorization.

721320233 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 326631 (or 326584 counting only the distinct ones).

The product of its (nonzero) digits is 1512, while the sum is 23.

The square root of 721320233 is about 26857.4055522867. The cubic root of 721320233 is about 896.8284387407.

The spelling of 721320233 in words is "seven hundred twenty-one million, three hundred twenty thousand, two hundred thirty-three".