221231028 has 24 divisors (see below), whose sum is σ = 519674400. Its totient is φ = 73248160.

The previous prime is 221231027. The next prime is 221231033. The reversal of 221231028 is 820132122.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 221230995 and 221231013.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221231027) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 60078 + ... + 63653.

It is an arithmetic number, because the mean of its divisors is an integer number (21653100).

Almost surely, 2^221231028 is an apocalyptic number.

It is an amenable number.

221231028 is an abundant number, since it is smaller than the sum of its proper divisors (298443372).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

221231028 is a wasteful number, since it uses less digits than its factorization.

221231028 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 123887 (or 123885 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 21.

The square root of 221231028 is about 14873.8370301681. The cubic root of 221231028 is about 604.8049622889.

The spelling of 221231028 in words is "two hundred twenty-one million, two hundred thirty-one thousand, twenty-eight".