21020131002021 has 4 divisors (see below), whose sum is σ = 28026841336032. Its totient is φ = 14013420668012.

The previous prime is 21020131001999. The next prime is 21020131002067. The reversal of 21020131002021 is 12020013102012.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21020131002021 - 2¹⁸ = 21020130739877 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21020131002071) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3503355167001 + ... + 3503355167006.

It is an arithmetic number, because the mean of its divisors is an integer number (7006710334008).

Almost surely, 2^{21020131002021} is an apocalyptic number.

It is an amenable number.

21020131002021 is a deficient number, since it is larger than the sum of its proper divisors (7006710334011).

21020131002021 is an equidigital number, since it uses as much as digits as its factorization.

21020131002021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7006710334010.

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

Adding to 21020131002021 its reverse (12020013102012), we get a palindrome (33040144104033).

The spelling of 21020131002021 in words is "twenty-one trillion, twenty billion, one hundred thirty-one million, two thousand, twenty-one".