21010011021 has 24 divisors (see below), whose sum is σ = 31379129600. Its totient is φ = 13532184000.

The previous prime is 21010010981. The next prime is 21010011047. The reversal of 21010011021 is 12011001012.

It is a happy number.

It is not a de Polignac number, because 21010011021 - 2¹⁴ = 21009994637 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21010010994 and 21010011012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21010011091) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 105030 + ... + 230328.

Almost surely, 2^21010011021 is an apocalyptic number.

It is an amenable number.

21010011021 is a deficient number, since it is larger than the sum of its proper divisors (10369118579).

21010011021 is a wasteful number, since it uses less digits than its factorization.

21010011021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 125937 (or 125934 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 9.

Adding to 21010011021 its reverse (12011001012), we get a palindrome (33021012033).

The spelling of 21010011021 in words is "twenty-one billion, ten million, eleven thousand, twenty-one".