201021100021 has 32 divisors (see below), whose sum is σ = 247042368000. Its totient is φ = 163179878400.

The previous prime is 201021099991. The next prime is 201021100057. The reversal of 201021100021 is 120001120102.

It is not a de Polignac number, because 201021100021 - 2⁹ = 201021099509 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 201021099980 and 201021100007.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (201021100061) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 670645 + ... + 922933.

It is an arithmetic number, because the mean of its divisors is an integer number (7720074000).

Almost surely, 2^201021100021 is an apocalyptic number.

It is an amenable number.

201021100021 is a deficient number, since it is larger than the sum of its proper divisors (46021267979).

201021100021 is a wasteful number, since it uses less digits than its factorization.

201021100021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 252434 (or 252420 counting only the distinct ones).

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

Adding to 201021100021 its reverse (120001120102), we get a palindrome (321022220123).

The spelling of 201021100021 in words is "two hundred one billion, twenty-one million, one hundred thousand, twenty-one".