21120100121 has 4 divisors (see below), whose sum is σ = 21165716352. Its totient is φ = 21074483892.

The previous prime is 21120100109. The next prime is 21120100147. The reversal of 21120100121 is 12100102112.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21120100121 - 2¹⁴ = 21120083737 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21120102121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 22807421 + ... + 22808346.

It is an arithmetic number, because the mean of its divisors is an integer number (5291429088).

Almost surely, 2^21120100121 is an apocalyptic number.

It is an amenable number.

21120100121 is a deficient number, since it is larger than the sum of its proper divisors (45616231).

21120100121 is an equidigital number, since it uses as much as digits as its factorization.

21120100121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45616230.

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

Adding to 21120100121 its reverse (12100102112), we get a palindrome (33220202233).

The spelling of 21120100121 in words is "twenty-one billion, one hundred twenty million, one hundred thousand, one hundred twenty-one".