728821915 has 4 divisors (see below), whose sum is σ = 874586304. Its totient is φ = 583057528.

The previous prime is 728821871. The next prime is 728821937. The reversal of 728821915 is 519128827.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 519128827 = 7 ⋅74161261.

It is a cyclic number.

It is not a de Polignac number, because 728821915 - 2⁹ = 728821403 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 72882187 + ... + 72882196.

It is an arithmetic number, because the mean of its divisors is an integer number (218646576).

Almost surely, 2^728821915 is an apocalyptic number.

728821915 is a deficient number, since it is larger than the sum of its proper divisors (145764389).

728821915 is a wasteful number, since it uses less digits than its factorization.

728821915 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 145764388.

The product of its digits is 80640, while the sum is 43.

The square root of 728821915 is about 26996.7019281986. The cubic root of 728821915 is about 899.9267080234.

The spelling of 728821915 in words is "seven hundred twenty-eight million, eight hundred twenty-one thousand, nine hundred fifteen".