21059218191 has 16 divisors (see below), whose sum is σ = 30635055360. Its totient is φ = 12761718720.

The previous prime is 21059218153. The next prime is 21059218237. The reversal of 21059218191 is 19181295012.

It is a happy number.

It is not a de Polignac number, because 21059218191 - 2⁹ = 21059217679 is a prime.

It is a super-2 number, since 2×21059218191² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21059298191) 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 15 ways as a sum of consecutive naturals, for example, 309390 + ... + 371268.

It is an arithmetic number, because the mean of its divisors is an integer number (1914690960).

Almost surely, 2^21059218191 is an apocalyptic number.

21059218191 is a deficient number, since it is larger than the sum of its proper divisors (9575837169).

21059218191 is a wasteful number, since it uses less digits than its factorization.

21059218191 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 72206.

The product of its (nonzero) digits is 12960, while the sum is 39.

It can be divided in two parts, 2105921 and 8191, that added together give a palindrome (2114112).

The spelling of 21059218191 in words is "twenty-one billion, fifty-nine million, two hundred eighteen thousand, one hundred ninety-one".