21475028191 has 2 divisors, whose sum is σ = 21475028192. Its totient is φ = 21475028190.

The previous prime is 21475028189. The next prime is 21475028209. The reversal of 21475028191 is 19182057412.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21475028191 - 2¹ = 21475028189 is a prime.

It is a super-2 number, since 2×21475028191² (a number of 21 digits) contains 22 as substring.

Together with 21475028189, 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 (21475028891) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10737514095 + 10737514096.

It is an arithmetic number, because the mean of its divisors is an integer number (10737514096).

Almost surely, 2^21475028191 is an apocalyptic number.

21475028191 is a deficient number, since it is larger than the sum of its proper divisors (1).

21475028191 is an equidigital number, since it uses as much as digits as its factorization.

21475028191 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 40320, while the sum is 40.

The spelling of 21475028191 in words is "twenty-one billion, four hundred seventy-five million, twenty-eight thousand, one hundred ninety-one".