721273601 has 4 divisors (see below), whose sum is σ = 727890900. Its totient is φ = 714656304.

The previous prime is 721273591. The next prime is 721273639. The reversal of 721273601 is 106372127.

721273601 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: 106372127 = 19 ⋅5598533.

It can be written as a sum of positive squares in 2 ways, for example, as 385101376 + 336172225 = 19624^2 + 18335^2 .

It is a cyclic number.

It is not a de Polignac number, because 721273601 - 2¹⁰ = 721272577 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (721273691) 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, 3308486 + ... + 3308703.

It is an arithmetic number, because the mean of its divisors is an integer number (181972725).

Almost surely, 2^721273601 is an apocalyptic number.

It is an amenable number.

721273601 is a deficient number, since it is larger than the sum of its proper divisors (6617299).

721273601 is a wasteful number, since it uses less digits than its factorization.

721273601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6617298.

The product of its (nonzero) digits is 3528, while the sum is 29.

The square root of 721273601 is about 26856.5373978106. The cubic root of 721273601 is about 896.8091122321.

The spelling of 721273601 in words is "seven hundred twenty-one million, two hundred seventy-three thousand, six hundred one".