221421155 has 24 divisors (see below), whose sum is σ = 285164784. Its totient is φ = 164980800.

The previous prime is 221421133. The next prime is 221421157. The reversal of 221421155 is 551124122.

It is not a de Polignac number, because 221421155 - 2⁶ = 221421091 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 221421155.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221421157) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 109100 + ... + 111110.

It is an arithmetic number, because the mean of its divisors is an integer number (11881866).

Almost surely, 2^221421155 is an apocalyptic number.

221421155 is a deficient number, since it is larger than the sum of its proper divisors (63743629).

221421155 is a wasteful number, since it uses less digits than its factorization.

221421155 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2115 (or 2096 counting only the distinct ones).

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

The square root of 221421155 is about 14880.2269807957. The cubic root of 221421155 is about 604.9781701023.

Adding to 221421155 its reverse (551124122), we get a palindrome (772545277).

The spelling of 221421155 in words is "two hundred twenty-one million, four hundred twenty-one thousand, one hundred fifty-five".