221543640 has 64 divisors (see below), whose sum is σ = 738482400. Its totient is φ = 59078016.

The previous prime is 221543603. The next prime is 221543653. The reversal of 221543640 is 46345122.

221543640 is a `hidden beast` number, since 2 + 2 + 15 + 4 + 3 + 640 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 101487 + ... + 103646.

Almost surely, 2^221543640 is an apocalyptic number.

221543640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

221543640 is an abundant number, since it is smaller than the sum of its proper divisors (516938760).

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

221543640 is a wasteful number, since it uses less digits than its factorization.

221543640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 205153 (or 205143 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 27.

The square root of 221543640 is about 14884.3421084037. The cubic root of 221543640 is about 605.0897027933.

Adding to 221543640 its reverse (46345122), we get a palindrome (267888762).

The spelling of 221543640 in words is "two hundred twenty-one million, five hundred forty-three thousand, six hundred forty".