221312424 has 32 divisors (see below), whose sum is σ = 566778240. Its totient is φ = 71971200.

The previous prime is 221312423. The next prime is 221312489. The reversal of 221312424 is 424213122.

221312424 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a nude number because it is divisible by every one of its digits.

It is a self number, because there is not a number n which added to its sum of digits gives 221312424.

It is not an unprimeable number, because it can be changed into a prime (221312423) 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, 111472 + ... + 113439.

It is an arithmetic number, because the mean of its divisors is an integer number (17711820).

Almost surely, 2^221312424 is an apocalyptic number.

221312424 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

221312424 is an abundant number, since it is smaller than the sum of its proper divisors (345465816).

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

221312424 is a wasteful number, since it uses less digits than its factorization.

221312424 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 224961 (or 224957 counting only the distinct ones).

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

The square root of 221312424 is about 14876.5729924603. The cubic root of 221312424 is about 604.8791270944.

Adding to 221312424 its reverse (424213122), we get a palindrome (645525546).

The spelling of 221312424 in words is "two hundred twenty-one million, three hundred twelve thousand, four hundred twenty-four".