21021110021 has 8 divisors (see below), whose sum is σ = 21406603104. Its totient is φ = 20636935920.

The previous prime is 21021109979. The next prime is 21021110029. The reversal of 21021110021 is 12001112012.

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 21021110021 - 2¹⁴ = 21021093637 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21021109984 and 21021110011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21021110029) 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, 297551 + ... + 361356.

It is an arithmetic number, because the mean of its divisors is an integer number (2675825388).

Almost surely, 2^21021110021 is an apocalyptic number.

It is an amenable number.

21021110021 is a deficient number, since it is larger than the sum of its proper divisors (385493083).

21021110021 is an equidigital number, since it uses as much as digits as its factorization.

21021110021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 659491.

The product of its (nonzero) digits is 8, while the sum is 11.

Adding to 21021110021 its reverse (12001112012), we get a palindrome (33022222033).

The spelling of 21021110021 in words is "twenty-one billion, twenty-one million, one hundred ten thousand, twenty-one".