221220426 has 16 divisors (see below), whose sum is σ = 505646784. Its totient is φ = 63205824.

The previous prime is 221220403. The next prime is 221220427. The reversal of 221220426 is 624022122.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (221220427) 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, 2633535 + ... + 2633618.

It is an arithmetic number, because the mean of its divisors is an integer number (31602924).

Almost surely, 2^221220426 is an apocalyptic number.

221220426 is an abundant number, since it is smaller than the sum of its proper divisors (284426358).

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

221220426 is a wasteful number, since it uses less digits than its factorization.

221220426 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5267165.

The product of its (nonzero) digits is 768, while the sum is 21.

The square root of 221220426 is about 14873.4806282860. The cubic root of 221220426 is about 604.7953008282.

Adding to 221220426 its reverse (624022122), we get a palindrome (845242548).

The spelling of 221220426 in words is "two hundred twenty-one million, two hundred twenty thousand, four hundred twenty-six".