21061210351 has 2 divisors, whose sum is σ = 21061210352. Its totient is φ = 21061210350.

The previous prime is 21061210349. The next prime is 21061210367. The reversal of 21061210351 is 15301216012.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21061210351 - 2¹ = 21061210349 is a prime.

Together with 21061210349, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21061210151) 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 as a sum of consecutive naturals, namely, 10530605175 + 10530605176.

It is an arithmetic number, because the mean of its divisors is an integer number (10530605176).

Almost surely, 2^21061210351 is an apocalyptic number.

21061210351 is a deficient number, since it is larger than the sum of its proper divisors (1).

21061210351 is an equidigital number, since it uses as much as digits as its factorization.

21061210351 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 360, while the sum is 22.

Adding to 21061210351 its reverse (15301216012), we get a palindrome (36362426363).

The spelling of 21061210351 in words is "twenty-one billion, sixty-one million, two hundred ten thousand, three hundred fifty-one".