221223928 has 8 divisors (see below), whose sum is σ = 414794880. Its totient is φ = 110611960.

The previous prime is 221223917. The next prime is 221223929. The reversal of 221223928 is 829322122.

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

It is a self number, because there is not a number n which added to its sum of digits gives 221223928.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221223929) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 13826488 + ... + 13826503.

It is an arithmetic number, because the mean of its divisors is an integer number (51849360).

Almost surely, 2^221223928 is an apocalyptic number.

It is an amenable number.

221223928 is a deficient number, since it is larger than the sum of its proper divisors (193570952).

221223928 is a wasteful number, since it uses less digits than its factorization.

221223928 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27652997 (or 27652993 counting only the distinct ones).

The product of its digits is 6912, while the sum is 31.

The square root of 221223928 is about 14873.5983541307. The cubic root of 221223928 is about 604.7984921880.

The spelling of 221223928 in words is "two hundred twenty-one million, two hundred twenty-three thousand, nine hundred twenty-eight".