221425861 has 4 divisors (see below), whose sum is σ = 224228800. Its totient is φ = 218622924.

The previous prime is 221425849. The next prime is 221425909. The reversal of 221425861 is 168524122.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 221425861 - 2¹⁵ = 221393093 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221425261) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1401351 + ... + 1401508.

It is an arithmetic number, because the mean of its divisors is an integer number (56057200).

Almost surely, 2^221425861 is an apocalyptic number.

It is an amenable number.

221425861 is a deficient number, since it is larger than the sum of its proper divisors (2802939).

221425861 is an equidigital number, since it uses as much as digits as its factorization.

221425861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2802938.

The product of its digits is 7680, while the sum is 31.

The square root of 221425861 is about 14880.3851092638. The cubic root of 221425861 is about 604.9824560630.

Adding to 221425861 its reverse (168524122), we get a palindrome (389949983).

The spelling of 221425861 in words is "two hundred twenty-one million, four hundred twenty-five thousand, eight hundred sixty-one".