21550221442 has 16 divisors (see below), whose sum is σ = 32520683520. Its totient is φ = 10710026512.

The previous prime is 21550221431. The next prime is 21550221481. The reversal of 21550221442 is 24412205512.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 21550221442.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2120409 + ... + 2130547.

It is an arithmetic number, because the mean of its divisors is an integer number (2032542720).

Almost surely, 2^21550221442 is an apocalyptic number.

21550221442 is a deficient number, since it is larger than the sum of its proper divisors (10970462078).

21550221442 is a wasteful number, since it uses less digits than its factorization.

21550221442 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16457.

The product of its (nonzero) digits is 6400, while the sum is 28.

Adding to 21550221442 its reverse (24412205512), we get a palindrome (45962426954).

The spelling of 21550221442 in words is "twenty-one billion, five hundred fifty million, two hundred twenty-one thousand, four hundred forty-two".