221212553 has 4 divisors (see below), whose sum is σ = 221815680. Its totient is φ = 220609428.

The previous prime is 221212543. The next prime is 221212613. The reversal of 221212553 is 355212122.

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 221212553 - 2⁶ = 221212489 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221212543) 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, 301013 + ... + 301746.

It is an arithmetic number, because the mean of its divisors is an integer number (55453920).

Almost surely, 2^221212553 is an apocalyptic number.

It is an amenable number.

221212553 is a deficient number, since it is larger than the sum of its proper divisors (603127).

221212553 is an equidigital number, since it uses as much as digits as its factorization.

221212553 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 603126.

The product of its digits is 1200, while the sum is 23.

The square root of 221212553 is about 14873.2159602421. The cubic root of 221212553 is about 604.7881260689.

Adding to 221212553 its reverse (355212122), we get a palindrome (576424675).

The spelling of 221212553 in words is "two hundred twenty-one million, two hundred twelve thousand, five hundred fifty-three".