221228837 has 16 divisors (see below), whose sum is σ = 251242560. Its totient is φ = 193519872.

The previous prime is 221228831. The next prime is 221228867. The reversal of 221228837 is 738822122.

It is a happy number.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-221228837 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 221228797 and 221228806.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221228831) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10658 + ... + 23580.

It is an arithmetic number, because the mean of its divisors is an integer number (15702660).

Almost surely, 2^221228837 is an apocalyptic number.

It is an amenable number.

221228837 is a deficient number, since it is larger than the sum of its proper divisors (30013723).

221228837 is a wasteful number, since it uses less digits than its factorization.

221228837 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13012.

The product of its digits is 21504, while the sum is 35.

The square root of 221228837 is about 14873.7633771685. The cubic root of 221228837 is about 604.8029656852.

The spelling of 221228837 in words is "two hundred twenty-one million, two hundred twenty-eight thousand, eight hundred thirty-seven".