21000310202021 has 4 divisors (see below), whose sum is σ = 21344577582444. Its totient is φ = 20656042821600.

The previous prime is 21000310201993. The next prime is 21000310202029. The reversal of 21000310202021 is 12020201300012.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 8122899004900 + 12877411197121 = 2850070^2 + 3588511^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21000310202021 is a prime.

It is a super-2 number, since 2×21000310202021² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21000310201987 and 21000310202005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21000310202029) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 172133690120 + ... + 172133690241.

It is an arithmetic number, because the mean of its divisors is an integer number (5336144395611).

Almost surely, 2^{21000310202021} is an apocalyptic number.

It is an amenable number.

21000310202021 is a deficient number, since it is larger than the sum of its proper divisors (344267380423).

21000310202021 is an equidigital number, since it uses as much as digits as its factorization.

21000310202021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 344267380422.

The product of its (nonzero) digits is 48, while the sum is 14.

Adding to 21000310202021 its reverse (12020201300012), we get a palindrome (33020511502033).

The spelling of 21000310202021 in words is "twenty-one trillion, three hundred ten million, two hundred two thousand, twenty-one".