221392128 has 144 divisors (see below), whose sum is σ = 618105600. Its totient is φ = 70287360.

The previous prime is 221392103. The next prime is 221392151. The reversal of 221392128 is 821293122.

It is a junction number, because it is equal to n+sod(n) for n = 221392095 and 221392104.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2487508 + ... + 2487596.

It is an arithmetic number, because the mean of its divisors is an integer number (4292400).

Almost surely, 2^221392128 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 221392128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (309052800).

221392128 is an abundant number, since it is smaller than the sum of its proper divisors (396713472).

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

221392128 is an equidigital number, since it uses as much as digits as its factorization.

221392128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 228 (or 214 counting only the distinct ones).

The product of its digits is 3456, while the sum is 30.

The square root of 221392128 is about 14879.2515940823. The cubic root of 221392128 is about 604.9517325972.

The spelling of 221392128 in words is "two hundred twenty-one million, three hundred ninety-two thousand, one hundred twenty-eight".