721689071 has 4 divisors (see below), whose sum is σ = 724372200. Its totient is φ = 719005944.

The previous prime is 721689047. The next prime is 721689113. The reversal of 721689071 is 170986127.

721689071 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 170986127 = 13 ⋅13152779.

It is a cyclic number.

It is not a de Polignac number, because 721689071 - 2¹⁰ = 721688047 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 (721689671) 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, 1341161 + ... + 1341698.

It is an arithmetic number, because the mean of its divisors is an integer number (181093050).

Almost surely, 2^721689071 is an apocalyptic number.

721689071 is a deficient number, since it is larger than the sum of its proper divisors (2683129).

721689071 is a wasteful number, since it uses less digits than its factorization.

721689071 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2683128.

The product of its (nonzero) digits is 42336, while the sum is 41.

The square root of 721689071 is about 26864.2712724541. The cubic root of 721689071 is about 896.9812733292.

The spelling of 721689071 in words is "seven hundred twenty-one million, six hundred eighty-nine thousand, seventy-one".