21100112121 has 32 divisors (see below), whose sum is σ = 31972631040. Its totient is φ = 12264540800.

The previous prime is 21100112107. The next prime is 21100112147. The reversal of 21100112121 is 12121100112.

It is a cyclic number.

It is not a de Polignac number, because 21100112121 - 2⁶ = 21100112057 is a prime.

It is a super-2 number, since 2×21100112121² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21100112097 and 21100112106.

It is not an unprimeable number, because it can be changed into a prime (21100112171) 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, 52335 + ... + 211988.

It is an arithmetic number, because the mean of its divisors is an integer number (999144720).

Almost surely, 2^21100112121 is an apocalyptic number.

It is an amenable number.

21100112121 is a deficient number, since it is larger than the sum of its proper divisors (10872518919).

21100112121 is a wasteful number, since it uses less digits than its factorization.

21100112121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 264437.

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

Adding to 21100112121 its reverse (12121100112), we get a palindrome (33221212233).

It can be divided in two parts, 21100112 and 121, that multiplied together give a palindrome (2553113552).

The spelling of 21100112121 in words is "twenty-one billion, one hundred million, one hundred twelve thousand, one hundred twenty-one".