21002013021 has 32 divisors (see below), whose sum is σ = 31582679040. Its totient is φ = 12298809600.

The previous prime is 21002013007. The next prime is 21002013031. The reversal of 21002013021 is 12031020012.

It is not a de Polignac number, because 21002013021 - 2¹¹ = 21002010973 is a prime.

It is a super-4 number, since 4×21002013021⁴ (a number of 42 digits) contains 4444 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21002012988 and 21002013006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21002013031) 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, 658581 + ... + 689733.

It is an arithmetic number, because the mean of its divisors is an integer number (986958720).

Almost surely, 2^21002013021 is an apocalyptic number.

It is an amenable number.

21002013021 is a deficient number, since it is larger than the sum of its proper divisors (10580666019).

21002013021 is a wasteful number, since it uses less digits than its factorization.

21002013021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31857.

The product of its (nonzero) digits is 24, while the sum is 12.

Adding to 21002013021 its reverse (12031020012), we get a palindrome (33033033033).

The spelling of 21002013021 in words is "twenty-one billion, two million, thirteen thousand, twenty-one".