221235872 has 72 divisors (see below), whose sum is σ = 514654560. Its totient is φ = 92801280.

The previous prime is 221235869. The next prime is 221235881. The reversal of 221235872 is 278532122.

221235872 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×221235872² = 97890622119200768, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (32).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 57629 + ... + 61347.

It is an arithmetic number, because the mean of its divisors is an integer number (7147980).

Almost surely, 2^221235872 is an apocalyptic number.

221235872 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 221235872, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (257327280).

221235872 is an abundant number, since it is smaller than the sum of its proper divisors (293418688).

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

221235872 is a wasteful number, since it uses less digits than its factorization.

221235872 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3766 (or 3745 counting only the distinct ones).

The product of its digits is 13440, while the sum is 32.

The square root of 221235872 is about 14873.9998655372. Note that the first 3 decimals coincide. The cubic root of 221235872 is about 604.8093764585.

221235872 divided by its sum of digits (32) gives a triangular number (6913621 = T₃₇₁₈).

Adding to 221235872 its reverse (278532122), we get a palindrome (499767994).

The spelling of 221235872 in words is "two hundred twenty-one million, two hundred thirty-five thousand, eight hundred seventy-two".