478939721 has 4 divisors (see below), whose sum is σ = 515781252. Its totient is φ = 442098192.

The previous prime is 478939717. The next prime is 478939723. The reversal of 478939721 is 127939874.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 252015625 + 226924096 = 15875^2 + 15064^2 .

It is a cyclic number.

It is not a de Polignac number, because 478939721 - 2² = 478939717 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 478939721.

It is not an unprimeable number, because it can be changed into a prime (478939723) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18420746 + ... + 18420771.

It is an arithmetic number, because the mean of its divisors is an integer number (128945313).

Almost surely, 2^478939721 is an apocalyptic number.

It is an amenable number.

478939721 is a deficient number, since it is larger than the sum of its proper divisors (36841531).

478939721 is a wasteful number, since it uses less digits than its factorization.

478939721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36841530.

The product of its digits is 762048, while the sum is 50.

The square root of 478939721 is about 21884.6914760067. The cubic root of 478939721 is about 782.3965960121.

The spelling of 478939721 in words is "four hundred seventy-eight million, nine hundred thirty-nine thousand, seven hundred twenty-one".