21231010021 has 8 divisors (see below), whose sum is σ = 23601718784. Its totient is φ = 18965666160.

The previous prime is 21231010013. The next prime is 21231010043. The reversal of 21231010021 is 12001013212.

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 21231010021 - 2³ = 21231010013 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (13).

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21231009983 and 21231010010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21231010061) 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, 26340801 + ... + 26341606.

It is an arithmetic number, because the mean of its divisors is an integer number (2950214848).

Almost surely, 2^21231010021 is an apocalyptic number.

It is an amenable number.

21231010021 is a deficient number, since it is larger than the sum of its proper divisors (2370708763).

21231010021 is a wasteful number, since it uses less digits than its factorization.

21231010021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52682451.

The product of its (nonzero) digits is 24, while the sum is 13.

Adding to 21231010021 its reverse (12001013212), we get a palindrome (33232023233).

The spelling of 21231010021 in words is "twenty-one billion, two hundred thirty-one million, ten thousand, twenty-one".