21201002121 has 16 divisors (see below), whose sum is σ = 30958441920. Its totient is φ = 12825637440.

The previous prime is 21201002111. The next prime is 21201002159. The reversal of 21201002121 is 12120010212.

It is not a de Polignac number, because 21201002121 - 2⁶ = 21201002057 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21201002097 and 21201002106.

It is not an unprimeable number, because it can be changed into a prime (21201002111) 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, 4604610 + ... + 4609211.

It is an arithmetic number, because the mean of its divisors is an integer number (1934902620).

Almost surely, 2^21201002121 is an apocalyptic number.

It is an amenable number.

21201002121 is a deficient number, since it is larger than the sum of its proper divisors (9757439799).

21201002121 is a wasteful number, since it uses less digits than its factorization.

21201002121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9213896.

The product of its (nonzero) digits is 16, while the sum is 12.

Adding to 21201002121 its reverse (12120010212), we get a palindrome (33321012333).

The spelling of 21201002121 in words is "twenty-one billion, two hundred one million, two thousand, one hundred twenty-one".