221320440 has 96 divisors (see below), whose sum is σ = 784695600. Its totient is φ = 53652480.

The previous prime is 221320427. The next prime is 221320447. The reversal of 221320440 is 44023122.

221320440 is a `hidden beast` number, since 221 + 3 + 2 + 0 + 440 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221320447) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 23985 + ... + 31904.

Almost surely, 2^221320440 is an apocalyptic number.

221320440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

221320440 is an abundant number, since it is smaller than the sum of its proper divisors (563375160).

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

221320440 is a wasteful number, since it uses less digits than its factorization.

221320440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55917 (or 55910 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 18.

The square root of 221320440 is about 14876.8424069088. The cubic root of 221320440 is about 604.8864299718.

Adding to 221320440 its reverse (44023122), we get a palindrome (265343562).

The spelling of 221320440 in words is "two hundred twenty-one million, three hundred twenty thousand, four hundred forty".