221423664 has 160 divisors (see below), whose sum is σ = 719953920. Its totient is φ = 56966400.

The previous prime is 221423633. The next prime is 221423681. The reversal of 221423664 is 466324122.

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 513529 + ... + 513959.

It is an arithmetic number, because the mean of its divisors is an integer number (4499712).

Almost surely, 2^221423664 is an apocalyptic number.

221423664 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 221423664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (359976960).

221423664 is an abundant number, since it is smaller than the sum of its proper divisors (498530256).

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

221423664 is a wasteful number, since it uses less digits than its factorization.

221423664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 599 (or 593 counting only the distinct ones).

The product of its digits is 13824, while the sum is 30.

The square root of 221423664 is about 14880.3112870665. The cubic root of 221423664 is about 604.9804551662.

Adding to 221423664 its reverse (466324122), we get a palindrome (687747786).

It can be divided in two parts, 2214 and 23664, that added together give a triangular number (25878 = T₂₂₇).

The spelling of 221423664 in words is "two hundred twenty-one million, four hundred twenty-three thousand, six hundred sixty-four".