221131540 has 24 divisors (see below), whose sum is σ = 530716032. Its totient is φ = 75816480.

The previous prime is 221131523. The next prime is 221131549. The reversal of 221131540 is 45131122.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221131549) 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 7 ways as a sum of consecutive naturals, for example, 789616 + ... + 789895.

It is an arithmetic number, because the mean of its divisors is an integer number (22113168).

Almost surely, 2^221131540 is an apocalyptic number.

221131540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

221131540 is an abundant number, since it is smaller than the sum of its proper divisors (309584492).

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

221131540 is a wasteful number, since it uses less digits than its factorization.

221131540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1579527 (or 1579525 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 19.

The square root of 221131540 is about 14870.4922581601. The cubic root of 221131540 is about 604.7142880609.

Adding to 221131540 its reverse (45131122), we get a palindrome (266262662).

It can be divided in two parts, 22113 and 1540, that added together give a triangular number (23653 = T₂₁₇).

The spelling of 221131540 in words is "two hundred twenty-one million, one hundred thirty-one thousand, five hundred forty".