21111200121 has 8 divisors (see below), whose sum is σ = 30707200224. Its totient is φ = 12794666720.

The previous prime is 21111200101. The next prime is 21111200153. The reversal of 21111200121 is 12100211112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21111200121 - 2²⁵ = 21077645689 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21111200097 and 21111200106.

It is not an unprimeable number, because it can be changed into a prime (21111200101) 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 7 ways as a sum of consecutive naturals, for example, 319866636 + ... + 319866701.

It is an arithmetic number, because the mean of its divisors is an integer number (3838400028).

Almost surely, 2^21111200121 is an apocalyptic number.

It is an amenable number.

21111200121 is a deficient number, since it is larger than the sum of its proper divisors (9596000103).

21111200121 is a wasteful number, since it uses less digits than its factorization.

21111200121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 639733351.

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

Adding to 21111200121 its reverse (12100211112), we get a palindrome (33211411233).

The spelling of 21111200121 in words is "twenty-one billion, one hundred eleven million, two hundred thousand, one hundred twenty-one".