721480009 has 4 divisors (see below), whose sum is σ = 746358660. Its totient is φ = 696601360.

The previous prime is 721480007. The next prime is 721480037. The reversal of 721480009 is 900084127.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 900084127 = 43 ⋅20932189.

It can be written as a sum of positive squares in 2 ways, for example, as 203689984 + 517790025 = 14272^2 + 22755^2 .

It is a cyclic number.

It is not a de Polignac number, because 721480009 - 2¹ = 721480007 is a prime.

It is a super-3 number, since 3×721480009³ (a number of 28 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (721480003) 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, 12439282 + ... + 12439339.

It is an arithmetic number, because the mean of its divisors is an integer number (186589665).

Almost surely, 2^721480009 is an apocalyptic number.

It is an amenable number.

721480009 is a deficient number, since it is larger than the sum of its proper divisors (24878651).

721480009 is a wasteful number, since it uses less digits than its factorization.

721480009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24878650.

The product of its (nonzero) digits is 4032, while the sum is 31.

The square root of 721480009 is about 26860.3799116840. The cubic root of 721480009 is about 896.8946511641.

The spelling of 721480009 in words is "seven hundred twenty-one million, four hundred eighty thousand, nine".