21210020101 has 4 divisors (see below), whose sum is σ = 22132194912. Its totient is φ = 20287845292.

The previous prime is 21210020053. The next prime is 21210020129. The reversal of 21210020101 is 10102001212.

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 21210020101 - 2⁷ = 21210019973 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21210020141) 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, 461087371 + ... + 461087416.

It is an arithmetic number, because the mean of its divisors is an integer number (5533048728).

Almost surely, 2^21210020101 is an apocalyptic number.

It is an amenable number.

21210020101 is a deficient number, since it is larger than the sum of its proper divisors (922174811).

21210020101 is an equidigital number, since it uses as much as digits as its factorization.

21210020101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 922174810.

The product of its (nonzero) digits is 8, while the sum is 10.

Adding to 21210020101 its reverse (10102001212), we get a palindrome (31312021313).

The spelling of 21210020101 in words is "twenty-one billion, two hundred ten million, twenty thousand, one hundred one".