721665056671037 has 2 divisors, whose sum is σ = 721665056671038. Its totient is φ = 721665056671036.

The previous prime is 721665056670923. The next prime is 721665056671057. The reversal of 721665056671037 is 730176650566127.

It is a happy number.

721665056671037 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 708649369779961 + 13015686891076 = 26620469^2 + 3607726^2 .

It is a cyclic number.

It is not a de Polignac number, because 721665056671037 - 2¹² = 721665056666941 is a prime.

It is a super-2 number, since 2×721665056671037² (a number of 31 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (721665056671057) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360832528335518 + 360832528335519.

It is an arithmetic number, because the mean of its divisors is an integer number (360832528335519).

Almost surely, 2^{721665056671037} is an apocalyptic number.

It is an amenable number.

721665056671037 is a deficient number, since it is larger than the sum of its proper divisors (1).

721665056671037 is an equidigital number, since it uses as much as digits as its factorization.

721665056671037 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 66679200, while the sum is 62.

The spelling of 721665056671037 in words is "seven hundred twenty-one trillion, six hundred sixty-five billion, fifty-six million, six hundred seventy-one thousand, thirty-seven".