21641193185 has 4 divisors (see below), whose sum is σ = 25969431828. Its totient is φ = 17312954544.

The previous prime is 21641193179. The next prime is 21641193191. The reversal of 21641193185 is 58139114612.

It is a happy number.

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

It is an interprime number because it is at equal distance from previous prime (21641193179) and next prime (21641193191).

It can be written as a sum of positive squares in 2 ways, for example, as 2523153361 + 19118039824 = 50231^2 + 138268^2 .

It is a cyclic number.

It is not a de Polignac number, because 21641193185 - 2⁴ = 21641193169 is a prime.

It is a Duffinian number.

It is an unprimeable number.

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 in 3 ways as a sum of consecutive naturals, for example, 2164119314 + ... + 2164119323.

It is an arithmetic number, because the mean of its divisors is an integer number (6492357957).

Almost surely, 2^21641193185 is an apocalyptic number.

It is an amenable number.

21641193185 is a deficient number, since it is larger than the sum of its proper divisors (4328238643).

21641193185 is an equidigital number, since it uses as much as digits as its factorization.

21641193185 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4328238642.

The product of its digits is 51840, while the sum is 41.

The spelling of 21641193185 in words is "twenty-one billion, six hundred forty-one million, one hundred ninety-three thousand, one hundred eighty-five".