721500001 has 8 divisors (see below), whose sum is σ = 741984264. Its totient is φ = 701153280.

The previous prime is 721499959. The next prime is 721500023. The reversal of 721500001 is 100005127.

It can be written as a sum of positive squares in 4 ways, for example, as 32490000 + 689010001 = 5700^2 + 26249^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 721500001 - 2¹⁷ = 721368929 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (721500071) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 23700 + ... + 44773.

It is an arithmetic number, because the mean of its divisors is an integer number (92748033).

Almost surely, 2^721500001 is an apocalyptic number.

It is an amenable number.

721500001 is a deficient number, since it is larger than the sum of its proper divisors (20484263).

721500001 is a wasteful number, since it uses less digits than its factorization.

721500001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 68771.

The product of its (nonzero) digits is 70, while the sum is 16.

The square root of 721500001 is about 26860.7520557411. The cubic root of 721500001 is about 896.9029353170.

Adding to 721500001 its reverse (100005127), we get a palindrome (821505128).

The spelling of 721500001 in words is "seven hundred twenty-one million, five hundred thousand, one".