721449985 has 4 divisors (see below), whose sum is σ = 865739988. Its totient is φ = 577159984.

The previous prime is 721449977. The next prime is 721449991. The reversal of 721449985 is 589944127.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 589944127 = 59 ⋅9999053.

It can be written as a sum of positive squares in 2 ways, for example, as 462594064 + 258855921 = 21508^2 + 16089^2 .

It is a cyclic number.

It is not a de Polignac number, because 721449985 - 2³ = 721449977 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 72144994 + ... + 72145003.

It is an arithmetic number, because the mean of its divisors is an integer number (216434997).

Almost surely, 2^721449985 is an apocalyptic number.

It is an amenable number.

721449985 is a deficient number, since it is larger than the sum of its proper divisors (144290003).

721449985 is a wasteful number, since it uses less digits than its factorization.

721449985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 144290002.

The product of its digits is 725760, while the sum is 49.

The square root of 721449985 is about 26859.8210157849. The cubic root of 721449985 is about 896.8822097297.

The spelling of 721449985 in words is "seven hundred twenty-one million, four hundred forty-nine thousand, nine hundred eighty-five".