721056667 has 4 divisors (see below), whose sum is σ = 745920720. Its totient is φ = 696192616.

The previous prime is 721056653. The next prime is 721056671. The reversal of 721056667 is 766650127.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 766650127 = 499 ⋅1536373.

It is a cyclic number.

It is not a de Polignac number, because 721056667 - 2¹¹ = 721054619 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (721056967) 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, 12431983 + ... + 12432040.

It is an arithmetic number, because the mean of its divisors is an integer number (186480180).

Almost surely, 2^721056667 is an apocalyptic number.

721056667 is a deficient number, since it is larger than the sum of its proper divisors (24864053).

721056667 is a wasteful number, since it uses less digits than its factorization.

721056667 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24864052.

The product of its (nonzero) digits is 105840, while the sum is 40.

The square root of 721056667 is about 26852.4983381435. The cubic root of 721056667 is about 896.7191935589.

The spelling of 721056667 in words is "seven hundred twenty-one million, fifty-six thousand, six hundred sixty-seven".