21365971859 has 4 divisors (see below), whose sum is σ = 21461783616. Its totient is φ = 21270160104.

The previous prime is 21365971853. The next prime is 21365971871. The reversal of 21365971859 is 95817956312.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21365971859 - 2⁴ = 21365971843 is a prime.

It is a super-3 number, since 3×21365971859³ (a number of 32 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21365971853) 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 in 3 ways as a sum of consecutive naturals, for example, 47905544 + ... + 47905989.

It is an arithmetic number, because the mean of its divisors is an integer number (5365445904).

Almost surely, 2^21365971859 is an apocalyptic number.

21365971859 is a deficient number, since it is larger than the sum of its proper divisors (95811757).

21365971859 is an equidigital number, since it uses as much as digits as its factorization.

21365971859 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 95811756.

The product of its digits is 4082400, while the sum is 56.

The spelling of 21365971859 in words is "twenty-one billion, three hundred sixty-five million, nine hundred seventy-one thousand, eight hundred fifty-nine".