21100124121 has 16 divisors (see below), whose sum is σ = 28227179520. Its totient is φ = 14019953040.

The previous prime is 21100124119. The next prime is 21100124161. The reversal of 21100124121 is 12142100112.

It is not a de Polignac number, because 21100124121 - 2¹ = 21100124119 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21100124121.

It is not an unprimeable number, because it can be changed into a prime (21100124161) 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, 2549436 + ... + 2557698.

It is an arithmetic number, because the mean of its divisors is an integer number (1764198720).

Almost surely, 2^21100124121 is an apocalyptic number.

It is an amenable number.

21100124121 is a deficient number, since it is larger than the sum of its proper divisors (7127055399).

21100124121 is a wasteful number, since it uses less digits than its factorization.

21100124121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10996.

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 21100124121 its reverse (12142100112), we get a palindrome (33242224233).

The spelling of 21100124121 in words is "twenty-one billion, one hundred million, one hundred twenty-four thousand, one hundred twenty-one".