21210131021 has 8 divisors (see below), whose sum is σ = 21316519224. Its totient is φ = 21104005120.

The previous prime is 21210130927. The next prime is 21210131051. The reversal of 21210131021 is 12013101212.

It can be written as a sum of positive squares in 4 ways, for example, as 7471009225 + 13739121796 = 86435^2 + 117214^2 .

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 21210131021 - 2²⁶ = 21143022157 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21210130987 and 21210131005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21210131051) 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 7 ways as a sum of consecutive naturals, for example, 97565 + ... + 227901.

It is an arithmetic number, because the mean of its divisors is an integer number (2664564903).

Almost surely, 2^21210131021 is an apocalyptic number.

It is an amenable number.

21210131021 is a deficient number, since it is larger than the sum of its proper divisors (106388203).

21210131021 is a wasteful number, since it uses less digits than its factorization.

21210131021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 131151.

The product of its (nonzero) digits is 24, while the sum is 14.

Adding to 21210131021 its reverse (12013101212), we get a palindrome (33223232233).

The spelling of 21210131021 in words is "twenty-one billion, two hundred ten million, one hundred thirty-one thousand, twenty-one".