721225577 has 2 divisors, whose sum is σ = 721225578. Its totient is φ = 721225576.

The previous prime is 721225573. The next prime is 721225591. The reversal of 721225577 is 775522127.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 696115456 + 25110121 = 26384^2 + 5011^2 .

It is a cyclic number.

It is not a de Polignac number, because 721225577 - 2² = 721225573 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 721225577.

It is not a weakly prime, because it can be changed into another prime (721225573) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360612788 + 360612789.

It is an arithmetic number, because the mean of its divisors is an integer number (360612789).

Almost surely, 2^721225577 is an apocalyptic number.

It is an amenable number.

721225577 is a deficient number, since it is larger than the sum of its proper divisors (1).

721225577 is an equidigital number, since it uses as much as digits as its factorization.

721225577 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 68600, while the sum is 38.

The square root of 721225577 is about 26855.6432989418. The cubic root of 721225577 is about 896.7892079422.

It can be divided in two parts, 721225 and 577, that multiplied together give a triangular number (416146825 = T₂₈₈₄₉).

The spelling of 721225577 in words is "seven hundred twenty-one million, two hundred twenty-five thousand, five hundred seventy-seven".