221236540 has 96 divisors (see below), whose sum is σ = 559448064. Its totient is φ = 71850240.

The previous prime is 221236523. The next prime is 221236597. The reversal of 221236540 is 45632122.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 408670 + ... + 409210.

It is an arithmetic number, because the mean of its divisors is an integer number (5827584).

Almost surely, 2^221236540 is an apocalyptic number.

221236540 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 221236540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (279724032).

221236540 is an abundant number, since it is smaller than the sum of its proper divisors (338211524).

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

221236540 is a wasteful number, since it uses less digits than its factorization.

221236540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 707 (or 705 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 25.

The square root of 221236540 is about 14874.0223208115. The cubic root of 221236540 is about 604.8099851787.

Adding to 221236540 its reverse (45632122), we get a palindrome (266868662).

The spelling of 221236540 in words is "two hundred twenty-one million, two hundred thirty-six thousand, five hundred forty".