21420321983 has 2 divisors, whose sum is σ = 21420321984. Its totient is φ = 21420321982.

The previous prime is 21420321961. The next prime is 21420322057. The reversal of 21420321983 is 38912302412.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21420321983 - 2¹⁰ = 21420320959 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21420321913) 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, 10710160991 + 10710160992.

It is an arithmetic number, because the mean of its divisors is an integer number (10710160992).

Almost surely, 2^21420321983 is an apocalyptic number.

21420321983 is a deficient number, since it is larger than the sum of its proper divisors (1).

21420321983 is an equidigital number, since it uses as much as digits as its factorization.

21420321983 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 20736, while the sum is 35.

The spelling of 21420321983 in words is "twenty-one billion, four hundred twenty million, three hundred twenty-one thousand, nine hundred eighty-three".