221243425 has 12 divisors (see below), whose sum is σ = 295445500. Its totient is φ = 163379520.

The previous prime is 221243413. The next prime is 221243431. The reversal of 221243425 is 524342122.

221243425 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 6 ways, for example, as 4064256 + 217179169 = 2016^2 + 14737^2 .

It is a de Polignac number, because none of the positive numbers 2^k-221243425 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is a self number, because there is not a number n which added to its sum of digits gives 221243425.

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, 340050 + ... + 340699.

Almost surely, 2^221243425 is an apocalyptic number.

221243425 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

221243425 is a deficient number, since it is larger than the sum of its proper divisors (74202075).

221243425 is a wasteful number, since it uses less digits than its factorization.

221243425 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 680772 (or 680767 counting only the distinct ones).

The product of its digits is 3840, while the sum is 25.

The square root of 221243425 is about 14874.2537627943. The cubic root of 221243425 is about 604.8162591176.

Adding to 221243425 its reverse (524342122), we get a palindrome (745585547).

The spelling of 221243425 in words is "two hundred twenty-one million, two hundred forty-three thousand, four hundred twenty-five".