21201030021 has 16 divisors (see below), whose sum is σ = 29938248000. Its totient is φ = 13299326208.

The previous prime is 21201029981. The next prime is 21201030077. The reversal of 21201030021 is 12003010212.

It is not a de Polignac number, because 21201030021 - 2⁶ = 21201029957 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21201029979 and 21201030006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21201030421) 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 15 ways as a sum of consecutive naturals, for example, 166530 + ... + 264828.

It is an arithmetic number, because the mean of its divisors is an integer number (1871140500).

Almost surely, 2^21201030021 is an apocalyptic number.

It is an amenable number.

21201030021 is a deficient number, since it is larger than the sum of its proper divisors (8737217979).

21201030021 is a wasteful number, since it uses less digits than its factorization.

21201030021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 102548.

The product of its (nonzero) digits is 24, while the sum is 12.

Adding to 21201030021 its reverse (12003010212), we get a palindrome (33204040233).

The spelling of 21201030021 in words is "twenty-one billion, two hundred one million, thirty thousand, twenty-one".