21021100121 has 16 divisors (see below), whose sum is σ = 24429767040. Its totient is φ = 17714885760.

The previous prime is 21021100073. The next prime is 21021100127. The reversal of 21021100121 is 12100112012.

It is not a de Polignac number, because 21021100121 - 2¹⁴ = 21021083737 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21021100127) 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, 201335 + ... + 287363.

It is an arithmetic number, because the mean of its divisors is an integer number (1526860440).

Almost surely, 2^21021100121 is an apocalyptic number.

It is an amenable number.

21021100121 is a deficient number, since it is larger than the sum of its proper divisors (3408666919).

21021100121 is an equidigital number, since it uses as much as digits as its factorization.

21021100121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 86624.

The product of its (nonzero) digits is 8, while the sum is 11.

Adding to 21021100121 its reverse (12100112012), we get a palindrome (33121212133).

The spelling of 21021100121 in words is "twenty-one billion, twenty-one million, one hundred thousand, one hundred twenty-one".