221424533551 has 16 divisors (see below), whose sum is σ = 246241330720. Its totient is φ = 197806976640.

The previous prime is 221424533543. The next prime is 221424533587. The reversal of 221424533551 is 155335424122.

It is a happy number.

It is not a de Polignac number, because 221424533551 - 2³ = 221424533543 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 221424533551.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221424533251) 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, 1756080 + ... + 1877941.

It is an arithmetic number, because the mean of its divisors is an integer number (15390083170).

Almost surely, 2^221424533551 is an apocalyptic number.

221424533551 is a deficient number, since it is larger than the sum of its proper divisors (24816797169).

221424533551 is a wasteful number, since it uses less digits than its factorization.

221424533551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3634186.

The product of its digits is 144000, while the sum is 37.

Adding to 221424533551 its reverse (155335424122), we get a palindrome (376759957673).

The spelling of 221424533551 in words is "two hundred twenty-one billion, four hundred twenty-four million, five hundred thirty-three thousand, five hundred fifty-one".