221234640 has 160 divisors (see below), whose sum is σ = 764522496. Its totient is φ = 52462080.

The previous prime is 221234639. The next prime is 221234659. The reversal of 221234640 is 46432122.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 221234640.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 123189 + ... + 124971.

Almost surely, 2^221234640 is an apocalyptic number.

221234640 is a gapful number since it is divisible by the number (20) 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 221234640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (382261248).

221234640 is an abundant number, since it is smaller than the sum of its proper divisors (543287856).

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

221234640 is a wasteful number, since it uses less digits than its factorization.

221234640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1857 (or 1851 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 24.

The square root of 221234640 is about 14873.9584509303. The cubic root of 221234640 is about 604.8082537856.

Adding to 221234640 its reverse (46432122), we get a palindrome (267666762).

The spelling of 221234640 in words is "two hundred twenty-one million, two hundred thirty-four thousand, six hundred forty".