221243541 has 16 divisors (see below), whose sum is σ = 297528000. Its totient is φ = 146233728.

The previous prime is 221243537. The next prime is 221243549. The reversal of 221243541 is 145342122.

It is not a de Polignac number, because 221243541 - 2² = 221243537 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221243549) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 210385 + ... + 211433.

It is an arithmetic number, because the mean of its divisors is an integer number (18595500).

Almost surely, 2^221243541 is an apocalyptic number.

It is an amenable number.

221243541 is a deficient number, since it is larger than the sum of its proper divisors (76284459).

221243541 is a wasteful number, since it uses less digits than its factorization.

221243541 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1588.

The product of its digits is 1920, while the sum is 24.

The square root of 221243541 is about 14874.2576621491. The cubic root of 221243541 is about 604.8163648211.

Adding to 221243541 its reverse (145342122), we get a palindrome (366585663).

It can be divided in two parts, 2212 and 43541, that added together give a triangular number (45753 = T₃₀₂).

The spelling of 221243541 in words is "two hundred twenty-one million, two hundred forty-three thousand, five hundred forty-one".