721955 has 16 divisors (see below), whose sum is σ = 967680. Its totient is φ = 513408.

The previous prime is 721951. The next prime is 721961. The reversal of 721955 is 559127.

It is a cyclic number.

It is not a de Polignac number, because 721955 - 2² = 721951 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (29).

It is not an unprimeable number, because it can be changed into a prime (721951) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1694 + ... + 2076.

It is an arithmetic number, because the mean of its divisors is an integer number (60480).

2⁷²¹⁹⁵⁵ is an apocalyptic number.

721955 is a deficient number, since it is larger than the sum of its proper divisors (245725).

721955 is a wasteful number, since it uses less digits than its factorization.

721955 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 430.

The product of its digits is 3150, while the sum is 29.

The square root of 721955 is about 849.6793512849. The cubic root of 721955 is about 89.7091433438.

The spelling of 721955 in words is "seven hundred twenty-one thousand, nine hundred fifty-five".