21303199861 has 2 divisors, whose sum is σ = 21303199862. Its totient is φ = 21303199860.

The previous prime is 21303199859. The next prime is 21303199867. The reversal of 21303199861 is 16899130312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12164987025 + 9138212836 = 110295^2 + 95594^2 .

It is a cyclic number.

It is not a de Polignac number, because 21303199861 - 2¹ = 21303199859 is a prime.

Together with 21303199859, 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 (21303199867) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10651599930 + 10651599931.

It is an arithmetic number, because the mean of its divisors is an integer number (10651599931).

Almost surely, 2^21303199861 is an apocalyptic number.

It is an amenable number.

21303199861 is a deficient number, since it is larger than the sum of its proper divisors (1).

21303199861 is an equidigital number, since it uses as much as digits as its factorization.

21303199861 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 69984, while the sum is 43.

The spelling of 21303199861 in words is "twenty-one billion, three hundred three million, one hundred ninety-nine thousand, eight hundred sixty-one".