21100101122121 has 32 divisors (see below), whose sum is σ = 32514414508800. Its totient is φ = 11921500968960.

The previous prime is 21100101122077. The next prime is 21100101122129. The reversal of 21100101122121 is 12122110100112.

It is a happy number.

It is not a de Polignac number, because 21100101122121 - 2¹⁰ = 21100101121097 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21100101122121.

It is not an unprimeable number, because it can be changed into a prime (21100101122129) 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, 179778385 + ... + 179895713.

It is an arithmetic number, because the mean of its divisors is an integer number (1016075453400).

Almost surely, 2^{21100101122121} is an apocalyptic number.

21100101122121 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21100101122121 is a deficient number, since it is larger than the sum of its proper divisors (11414313386679).

21100101122121 is a wasteful number, since it uses less digits than its factorization.

21100101122121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 213649.

The product of its (nonzero) digits is 16, while the sum is 15.

Adding to 21100101122121 its reverse (12122110100112), we get a palindrome (33222211222233).

The spelling of 21100101122121 in words is "twenty-one trillion, one hundred billion, one hundred one million, one hundred twenty-two thousand, one hundred twenty-one".