21012302021 has 2 divisors, whose sum is σ = 21012302022. Its totient is φ = 21012302020.

The previous prime is 21012301991. The next prime is 21012302023. The reversal of 21012302021 is 12020321012.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10865769121 + 10146532900 = 104239^2 + 100730^2 .

It is a cyclic number.

It is not a de Polignac number, because 21012302021 - 2⁶ = 21012301957 is a prime.

Together with 21012302023, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 21012301987 and 21012302005.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21012302023) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10506151010 + 10506151011.

It is an arithmetic number, because the mean of its divisors is an integer number (10506151011).

Almost surely, 2^21012302021 is an apocalyptic number.

It is an amenable number.

21012302021 is a deficient number, since it is larger than the sum of its proper divisors (1).

21012302021 is an equidigital number, since it uses as much as digits as its factorization.

21012302021 is an evil number, because the sum of its binary digits is even.

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

Adding to 21012302021 its reverse (12020321012), we get a palindrome (33032623033).

The spelling of 21012302021 in words is "twenty-one billion, twelve million, three hundred two thousand, twenty-one".