21100220121 has 8 divisors (see below), whose sum is σ = 28134587680. Its totient is φ = 14066332992.

The previous prime is 21100220111. The next prime is 21100220131. The reversal of 21100220121 is 12102200112.

It is an interprime number because it is at equal distance from previous prime (21100220111) and next prime (21100220131).

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

It is not a de Polignac number, because 21100220121 - 2¹⁰ = 21100219097 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21100220097 and 21100220106.

It is not an unprimeable number, because it can be changed into a prime (21100220101) 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, 655 + ... + 205428.

It is an arithmetic number, because the mean of its divisors is an integer number (3516823460).

Almost surely, 2^21100220121 is an apocalyptic number.

It is an amenable number.

21100220121 is a deficient number, since it is larger than the sum of its proper divisors (7034367559).

21100220121 is a wasteful number, since it uses less digits than its factorization.

21100220121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 240215.

The product of its (nonzero) digits is 16, while the sum is 12.

Adding to 21100220121 its reverse (12102200112), we get a palindrome (33202420233).

The spelling of 21100220121 in words is "twenty-one billion, one hundred million, two hundred twenty thousand, one hundred twenty-one".