221215541 has 8 divisors (see below), whose sum is σ = 236464704. Its totient is φ = 206435680.

The previous prime is 221215529. The next prime is 221215571. The reversal of 221215541 is 145512122.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 221215541 - 2²² = 217021237 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (23).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221215571) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 116351 + ... + 118236.

It is an arithmetic number, because the mean of its divisors is an integer number (29558088).

Almost surely, 2^221215541 is an apocalyptic number.

It is an amenable number.

221215541 is a deficient number, since it is larger than the sum of its proper divisors (15249163).

221215541 is a wasteful number, since it uses less digits than its factorization.

221215541 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 234651.

The product of its digits is 800, while the sum is 23.

The square root of 221215541 is about 14873.3164089251. The cubic root of 221215541 is about 604.7908490892.

Adding to 221215541 its reverse (145512122), we get a palindrome (366727663).

The spelling of 221215541 in words is "two hundred twenty-one million, two hundred fifteen thousand, five hundred forty-one".