21321310019951 has 2 divisors, whose sum is σ = 21321310019952. Its totient is φ = 21321310019950.

The previous prime is 21321310019917. The next prime is 21321310020011. The reversal of 21321310019951 is 15991001312312.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21321310019951 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21321010019951) 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, 10660655009975 + 10660655009976.

It is an arithmetic number, because the mean of its divisors is an integer number (10660655009976).

Almost surely, 2^{21321310019951} is an apocalyptic number.

21321310019951 is a deficient number, since it is larger than the sum of its proper divisors (1).

21321310019951 is an equidigital number, since it uses as much as digits as its factorization.

21321310019951 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 14580, while the sum is 38.

The spelling of 21321310019951 in words is "twenty-one trillion, three hundred twenty-one billion, three hundred ten million, nineteen thousand, nine hundred fifty-one".