721428399 has 12 divisors (see below), whose sum is σ = 1042587000. Its totient is φ = 480710544.

The previous prime is 721428359. The next prime is 721428443. The reversal of 721428399 is 993824127.

721428399 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 721428399 - 2¹² = 721424303 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721428319) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 204 + ... + 37985.

It is an arithmetic number, because the mean of its divisors is an integer number (86882250).

Almost surely, 2^721428399 is an apocalyptic number.

721428399 is a deficient number, since it is larger than the sum of its proper divisors (321158601).

721428399 is a wasteful number, since it uses less digits than its factorization.

721428399 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40294 (or 40291 counting only the distinct ones).

The product of its digits is 217728, while the sum is 45.

The square root of 721428399 is about 26859.4191858275. The cubic root of 721428399 is about 896.8732646456.

Adding to 721428399 its product of digits (217728), we get a palindrome (721646127).

The spelling of 721428399 in words is "seven hundred twenty-one million, four hundred twenty-eight thousand, three hundred ninety-nine".