721955005 has 4 divisors (see below), whose sum is σ = 866346012. Its totient is φ = 577564000.

The previous prime is 721954973. The next prime is 721955041. The reversal of 721955005 is 500559127.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 500559127 = 59 ⋅8484053.

It can be written as a sum of positive squares in 2 ways, for example, as 116942596 + 605012409 = 10814^2 + 24597^2 .

It is not a de Polignac number, because 721955005 - 2⁵ = 721954973 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 72195496 + ... + 72195505.

It is an arithmetic number, because the mean of its divisors is an integer number (216586503).

Almost surely, 2^721955005 is an apocalyptic number.

It is an amenable number.

721955005 is a deficient number, since it is larger than the sum of its proper divisors (144391007).

721955005 is a wasteful number, since it uses less digits than its factorization.

721955005 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 144391006.

The product of its (nonzero) digits is 15750, while the sum is 34.

The square root of 721955005 is about 26869.2204017906. The cubic root of 721955005 is about 897.0914355094.

The spelling of 721955005 in words is "seven hundred twenty-one million, nine hundred fifty-five thousand, five".