21001210002021 has 4 divisors (see below), whose sum is σ = 28001613336032. Its totient is φ = 14000806668012.

The previous prime is 21001210002001. The next prime is 21001210002023. The reversal of 21001210002021 is 12020001210012.

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 not a de Polignac number, because 21001210002021 - 2⁹ = 21001210001509 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21001210001988 and 21001210002006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21001210002023) 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, 3500201667001 + ... + 3500201667006.

It is an arithmetic number, because the mean of its divisors is an integer number (7000403334008).

Almost surely, 2^{21001210002021} is an apocalyptic number.

It is an amenable number.

21001210002021 is a deficient number, since it is larger than the sum of its proper divisors (7000403334011).

21001210002021 is an equidigital number, since it uses as much as digits as its factorization.

21001210002021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7000403334010.

The product of its (nonzero) digits is 16, while the sum is 12.

Adding to 21001210002021 its reverse (12020001210012), we get a palindrome (33021211212033).

The spelling of 21001210002021 in words is "twenty-one trillion, one billion, two hundred ten million, two thousand, twenty-one".