221542261 has 4 divisors (see below), whose sum is σ = 233202400. Its totient is φ = 209882124.

The previous prime is 221542247. The next prime is 221542291. The reversal of 221542261 is 162245122.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 221542261 - 2¹¹ = 221540213 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221542241) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 5830041 + ... + 5830078.

It is an arithmetic number, because the mean of its divisors is an integer number (58300600).

Almost surely, 2^221542261 is an apocalyptic number.

It is an amenable number.

221542261 is a deficient number, since it is larger than the sum of its proper divisors (11660139).

221542261 is a wasteful number, since it uses less digits than its factorization.

221542261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11660138.

The product of its digits is 1920, while the sum is 25.

The square root of 221542261 is about 14884.2957844837. The cubic root of 221542261 is about 605.0884473289.

Adding to 221542261 its reverse (162245122), we get a palindrome (383787383).

The spelling of 221542261 in words is "two hundred twenty-one million, five hundred forty-two thousand, two hundred sixty-one".