21210201021 has 4 divisors (see below), whose sum is σ = 28280268032. Its totient is φ = 14140134012.

The previous prime is 21210201013. The next prime is 21210201041. The reversal of 21210201021 is 12010201212.

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 not a de Polignac number, because 21210201021 - 2³ = 21210201013 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21210200988 and 21210201006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21210201041) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3535033501 + ... + 3535033506.

It is an arithmetic number, because the mean of its divisors is an integer number (7070067008).

Almost surely, 2^21210201021 is an apocalyptic number.

It is an amenable number.

21210201021 is a deficient number, since it is larger than the sum of its proper divisors (7070067011).

21210201021 is an equidigital number, since it uses as much as digits as its factorization.

21210201021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7070067010.

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

Adding to 21210201021 its reverse (12010201212), we get a palindrome (33220402233).

The spelling of 21210201021 in words is "twenty-one billion, two hundred ten million, two hundred one thousand, twenty-one".