721740577 has 4 divisors (see below), whose sum is σ = 725728276. Its totient is φ = 717752880.

The previous prime is 721740533. The next prime is 721740581. The reversal of 721740577 is 775047127.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 57699216 + 664041361 = 7596^2 + 25769^2 .

It is a cyclic number.

It is not a de Polignac number, because 721740577 - 2⁷ = 721740449 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (721740587) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1993578 + ... + 1993939.

It is an arithmetic number, because the mean of its divisors is an integer number (181432069).

Almost surely, 2^721740577 is an apocalyptic number.

It is an amenable number.

721740577 is a deficient number, since it is larger than the sum of its proper divisors (3987699).

721740577 is a wasteful number, since it uses less digits than its factorization.

721740577 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3987698.

The product of its (nonzero) digits is 96040, while the sum is 40.

The square root of 721740577 is about 26865.2298892081. The cubic root of 721740577 is about 897.0026116129.

The spelling of 721740577 in words is "seven hundred twenty-one million, seven hundred forty thousand, five hundred seventy-seven".