21231021021 has 64 divisors (see below), whose sum is σ = 35021414400. Its totient is φ = 11169446400.

The previous prime is 21231021011. The next prime is 21231021041. The reversal of 21231021021 is 12012013212.

It is not a de Polignac number, because 21231021021 - 2¹⁴ = 21231004637 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21231021001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 4430895 + ... + 4435683.

It is an arithmetic number, because the mean of its divisors is an integer number (547209600).

Almost surely, 2^21231021021 is an apocalyptic number.

21231021021 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21231021021 is a deficient number, since it is larger than the sum of its proper divisors (13790393379).

21231021021 is a wasteful number, since it uses less digits than its factorization.

21231021021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5130.

The product of its (nonzero) digits is 48, while the sum is 15.

Adding to 21231021021 its reverse (12012013212), we get a palindrome (33243034233).

The spelling of 21231021021 in words is "twenty-one billion, two hundred thirty-one million, twenty-one thousand, twenty-one".