21301021021 has 16 divisors (see below), whose sum is σ = 24862723200. Its totient is φ = 17870643648.

The previous prime is 21301020971. The next prime is 21301021033. The reversal of 21301021021 is 12012010312.

It is a cyclic number.

It is not a de Polignac number, because 21301021021 - 2²⁵ = 21267466589 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21301020992 and 21301021010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21301001021) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 86935 + ... + 223963.

It is an arithmetic number, because the mean of its divisors is an integer number (1553920200).

Almost surely, 2^21301021021 is an apocalyptic number.

It is an amenable number.

21301021021 is a deficient number, since it is larger than the sum of its proper divisors (3561702179).

21301021021 is a wasteful number, since it uses less digits than its factorization.

21301021021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 137508.

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

Adding to 21301021021 its reverse (12012010312), we get a palindrome (33313031333).

The spelling of 21301021021 in words is "twenty-one billion, three hundred one million, twenty-one thousand, twenty-one".