21221100355 has 32 divisors (see below), whose sum is σ = 31482630144. Its totient is φ = 13371958656.

The previous prime is 21221100337. The next prime is 21221100359. The reversal of 21221100355 is 55300112212.

It is not a de Polignac number, because 21221100355 - 2³¹ = 19073616707 is a prime.

It is a super-2 number, since 2×21221100355² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21221100359) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3109 + ... + 206038.

It is an arithmetic number, because the mean of its divisors is an integer number (983832192).

Almost surely, 2^21221100355 is an apocalyptic number.

21221100355 is a deficient number, since it is larger than the sum of its proper divisors (10261529789).

21221100355 is a wasteful number, since it uses less digits than its factorization.

21221100355 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 209395.

The product of its (nonzero) digits is 600, while the sum is 22.

Adding to 21221100355 its reverse (55300112212), we get a palindrome (76521212567).

The spelling of 21221100355 in words is "twenty-one billion, two hundred twenty-one million, one hundred thousand, three hundred fifty-five".