721609033 has 2 divisors, whose sum is σ = 721609034. Its totient is φ = 721609032.

The previous prime is 721609019. The next prime is 721609043. The reversal of 721609033 is 330906127.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 577537024 + 144072009 = 24032^2 + 12003^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-721609033 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 721608986 and 721609004.

It is not a weakly prime, because it can be changed into another prime (721609043) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360804516 + 360804517.

It is an arithmetic number, because the mean of its divisors is an integer number (360804517).

Almost surely, 2^721609033 is an apocalyptic number.

It is an amenable number.

721609033 is a deficient number, since it is larger than the sum of its proper divisors (1).

721609033 is an equidigital number, since it uses as much as digits as its factorization.

721609033 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6804, while the sum is 31.

The square root of 721609033 is about 26862.7815573890. The cubic root of 721609033 is about 896.9481125844.

The spelling of 721609033 in words is "seven hundred twenty-one million, six hundred nine thousand, thirty-three".