721665056670037 has 4 divisors (see below), whose sum is σ = 721736785639116. Its totient is φ = 721593327700960.

The previous prime is 721665056670029. The next prime is 721665056670121. The reversal of 721665056670037 is 730076650566127.

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 575424431856036 + 146240624814001 = 23988006^2 + 12092999^2 .

It is a cyclic number.

It is not a de Polignac number, because 721665056670037 - 2³ = 721665056670029 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721665056671037) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 35864469448 + ... + 35864489569.

It is an arithmetic number, because the mean of its divisors is an integer number (180434196409779).

Almost surely, 2^{721665056670037} is an apocalyptic number.

It is an amenable number.

721665056670037 is a deficient number, since it is larger than the sum of its proper divisors (71728969079).

721665056670037 is a wasteful number, since it uses less digits than its factorization.

721665056670037 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71728969078.

The product of its (nonzero) digits is 66679200, while the sum is 61.

The spelling of 721665056670037 in words is "seven hundred twenty-one trillion, six hundred sixty-five billion, fifty-six million, six hundred seventy thousand, thirty-seven".