721428613 has 8 divisors (see below), whose sum is σ = 768549600. Its totient is φ = 675222768.

The previous prime is 721428607. The next prime is 721428629. The reversal of 721428613 is 316824127.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-721428613 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721428013) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 227158 + ... + 230311.

It is an arithmetic number, because the mean of its divisors is an integer number (96068700).

Almost surely, 2^721428613 is an apocalyptic number.

It is an amenable number.

721428613 is a deficient number, since it is larger than the sum of its proper divisors (47120987).

721428613 is a wasteful number, since it uses less digits than its factorization.

721428613 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 457571.

The product of its digits is 16128, while the sum is 34.

The square root of 721428613 is about 26859.4231695321. The cubic root of 721428613 is about 896.8733533265.

The spelling of 721428613 in words is "seven hundred twenty-one million, four hundred twenty-eight thousand, six hundred thirteen".