721006789 has 2 divisors, whose sum is σ = 721006790. Its totient is φ = 721006788.

The previous prime is 721006733. The next prime is 721006799. The reversal of 721006789 is 987600127.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 663474564 + 57532225 = 25758^2 + 7585^2 .

It is a cyclic number.

It is not a de Polignac number, because 721006789 - 2¹⁵ = 720974021 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (721006709) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360503394 + 360503395.

It is an arithmetic number, because the mean of its divisors is an integer number (360503395).

Almost surely, 2^721006789 is an apocalyptic number.

It is an amenable number.

721006789 is a deficient number, since it is larger than the sum of its proper divisors (1).

721006789 is an equidigital number, since it uses as much as digits as its factorization.

721006789 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 42336, while the sum is 40.

The square root of 721006789 is about 26851.5695816837. The cubic root of 721006789 is about 896.6985166860.

The spelling of 721006789 in words is "seven hundred twenty-one million, six thousand, seven hundred eighty-nine".