16635454522221 has 16 divisors (see below), whose sum is σ = 22461556981760. Its totient is φ = 10949829836400.

The previous prime is 16635454522189. The next prime is 16635454522259. The reversal of 16635454522221 is 12222545453661.

It is not a de Polignac number, because 16635454522221 - 2⁵ = 16635454522189 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16635454520221) 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, 41603796 + ... + 42001746.

It is an arithmetic number, because the mean of its divisors is an integer number (1403847311360).

Almost surely, 2^{16635454522221} is an apocalyptic number.

It is an amenable number.

16635454522221 is a deficient number, since it is larger than the sum of its proper divisors (5826102459539).

16635454522221 is a wasteful number, since it uses less digits than its factorization.

16635454522221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 574416.

The product of its digits is 3456000, while the sum is 48.

Adding to 16635454522221 its reverse (12222545453661), we get a palindrome (28857999975882).

The spelling of 16635454522221 in words is "sixteen trillion, six hundred thirty-five billion, four hundred fifty-four million, five hundred twenty-two thousand, two hundred twenty-one".