21211010121 has 16 divisors (see below), whose sum is σ = 32730675200. Its totient is φ = 11967151248.

The previous prime is 21211010099. The next prime is 21211010129. The reversal of 21211010121 is 12101011212.

It is not a de Polignac number, because 21211010121 - 2¹⁵ = 21210977353 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21211010097 and 21211010106.

It is not an unprimeable number, because it can be changed into a prime (21211010129) 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, 6391051 + ... + 6394368.

It is an arithmetic number, because the mean of its divisors is an integer number (2045667200).

Almost surely, 2^21211010121 is an apocalyptic number.

21211010121 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21211010121 is a deficient number, since it is larger than the sum of its proper divisors (11519665079).

21211010121 is a wasteful number, since it uses less digits than its factorization.

21211010121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12785508.

The product of its (nonzero) digits is 8, while the sum is 12.

Adding to 21211010121 its reverse (12101011212), we get a palindrome (33312021333).

The spelling of 21211010121 in words is "twenty-one billion, two hundred eleven million, ten thousand, one hundred twenty-one".