721375057 has 4 divisors (see below), whose sum is σ = 776865460. Its totient is φ = 665884656.

The previous prime is 721375043. The next prime is 721375091. The reversal of 721375057 is 750573127.

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 99920016 + 621455041 = 9996^2 + 24929^2 .

It is a cyclic number.

It is not a de Polignac number, because 721375057 - 2¹⁹ = 720850769 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (721375157) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 27745182 + ... + 27745207.

It is an arithmetic number, because the mean of its divisors is an integer number (194216365).

Almost surely, 2^721375057 is an apocalyptic number.

It is an amenable number.

721375057 is a deficient number, since it is larger than the sum of its proper divisors (55490403).

721375057 is a wasteful number, since it uses less digits than its factorization.

721375057 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55490402.

The product of its (nonzero) digits is 51450, while the sum is 37.

The square root of 721375057 is about 26858.4261824851. The cubic root of 721375057 is about 896.8511593367.

The spelling of 721375057 in words is "seven hundred twenty-one million, three hundred seventy-five thousand, fifty-seven".