706721 has 4 divisors (see below), whose sum is σ = 737472. Its totient is φ = 675972.

The previous prime is 706709. The next prime is 706729. The reversal of 706721 is 127607.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-706721 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (23), and also a Moran number because the ratio is a prime number: 30727 = 706721 / (7 + 0 + 6 + 7 + 2 + 1).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (706729) 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, 15341 + ... + 15386.

It is an arithmetic number, because the mean of its divisors is an integer number (184368).

2⁷⁰⁶⁷²¹ is an apocalyptic number.

It is an amenable number.

706721 is a deficient number, since it is larger than the sum of its proper divisors (30751).

706721 is a wasteful number, since it uses less digits than its factorization.

706721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30750.

The product of its (nonzero) digits is 588, while the sum is 23.

The square root of 706721 is about 840.6669970922. Note that the first 3 decimals coincide. The cubic root of 706721 is about 89.0736670721.

The spelling of 706721 in words is "seven hundred six thousand, seven hundred twenty-one".