21020110021 has 8 divisors (see below), whose sum is σ = 21936426624. Its totient is φ = 20103993360.

The previous prime is 21020110019. The next prime is 21020110043. The reversal of 21020110021 is 12001102012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21020110021 - 2¹ = 21020110019 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21020110091) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 189280 + ... + 279046.

It is an arithmetic number, because the mean of its divisors is an integer number (2742053328).

Almost surely, 2^21020110021 is an apocalyptic number.

It is an amenable number.

21020110021 is a deficient number, since it is larger than the sum of its proper divisors (916316603).

21020110021 is a wasteful number, since it uses less digits than its factorization.

21020110021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 99971.

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

Adding to 21020110021 its reverse (12001102012), we get a palindrome (33021212033).

The spelling of 21020110021 in words is "twenty-one billion, twenty million, one hundred ten thousand, twenty-one".