728157224 has 8 divisors (see below), whose sum is σ = 1365294810. Its totient is φ = 364078608.

The previous prime is 728157191. The next prime is 728157239. The reversal of 728157224 is 422751827.

It can be written as a sum of positive squares in only one way, i.e., 721996900 + 6160324 = 26870^2 + 2482^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45509819 + ... + 45509834.

Almost surely, 2^728157224 is an apocalyptic number.

It is an amenable number.

728157224 is a deficient number, since it is larger than the sum of its proper divisors (637137586).

728157224 is a wasteful number, since it uses less digits than its factorization.

728157224 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 91019659 (or 91019655 counting only the distinct ones).

The product of its digits is 62720, while the sum is 38.

The square root of 728157224 is about 26984.3885237372. The cubic root of 728157224 is about 899.6530448648.

The spelling of 728157224 in words is "seven hundred twenty-eight million, one hundred fifty-seven thousand, two hundred twenty-four".