19720228 has 12 divisors (see below), whose sum is σ = 37647792. Its totient is φ = 8963720.

The previous prime is 19720193. The next prime is 19720231. The reversal of 19720228 is 82202791.

It is a self number, because there is not a number n which added to its sum of digits gives 19720228.

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, 224050 + ... + 224137.

It is an arithmetic number, because the mean of its divisors is an integer number (3137316).

Almost surely, 2^19720228 is an apocalyptic number.

It is an amenable number.

19720228 is a deficient number, since it is larger than the sum of its proper divisors (17927564).

19720228 is a wasteful number, since it uses less digits than its factorization.

19720228 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 448202 (or 448200 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 31.

The square root of 19720228 is about 4440.7463336696. The cubic root of 19720228 is about 270.1701168445.

The spelling of 19720228 in words is "nineteen million, seven hundred twenty thousand, two hundred twenty-eight".