221521140 has 72 divisors (see below), whose sum is σ = 695134440. Its totient is φ = 57033984.

The previous prime is 221521129. The next prime is 221521151. The reversal of 221521140 is 41125122.

221521140 is a `hidden beast` number, since 2 + 2 + 1 + 521 + 140 = 666.

It is an interprime number because it is at equal distance from previous prime (221521129) and next prime (221521151).

It can be written as a sum of positive squares in 4 ways, for example, as 96707556 + 124813584 = 9834^2 + 11172^2 .

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

It is a congruent number.

It is an unprimeable number.

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, 15999 + ... + 26438.

It is an arithmetic number, because the mean of its divisors is an integer number (9654645).

Almost surely, 2^221521140 is an apocalyptic number.

221521140 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

221521140 is an abundant number, since it is smaller than the sum of its proper divisors (473613300).

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

221521140 is a wasteful number, since it uses less digits than its factorization.

221521140 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42481 (or 42476 counting only the distinct ones).

The product of its (nonzero) digits is 160, while the sum is 18.

The square root of 221521140 is about 14883.5862613820. The cubic root of 221521140 is about 605.0692177709.

Adding to 221521140 its reverse (41125122), we get a palindrome (262646262).

The spelling of 221521140 in words is "two hundred twenty-one million, five hundred twenty-one thousand, one hundred forty".