21221100121 has 8 divisors (see below), whose sum is σ = 23847122880. Its totient is φ = 18737024592.

The previous prime is 21221100101. The next prime is 21221100149. The reversal of 21221100121 is 12100112212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21221100121 - 2¹⁹ = 21220575833 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (13).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21221100101) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 35486491 + ... + 35487088.

It is an arithmetic number, because the mean of its divisors is an integer number (2980890360).

Almost surely, 2^21221100121 is an apocalyptic number.

It is an amenable number.

21221100121 is a deficient number, since it is larger than the sum of its proper divisors (2626022759).

21221100121 is a wasteful number, since it uses less digits than its factorization.

21221100121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 70973615.

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 21221100121 its reverse (12100112212), we get a palindrome (33321212333).

The spelling of 21221100121 in words is "twenty-one billion, two hundred twenty-one million, one hundred thousand, one hundred twenty-one".