21045647191 has 2 divisors, whose sum is σ = 21045647192. Its totient is φ = 21045647190.

The previous prime is 21045647177. The next prime is 21045647209. The reversal of 21045647191 is 19174654012.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21045647191 - 2¹¹ = 21045645143 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21045647171) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10522823595 + 10522823596.

It is an arithmetic number, because the mean of its divisors is an integer number (10522823596).

Almost surely, 2^21045647191 is an apocalyptic number.

21045647191 is a deficient number, since it is larger than the sum of its proper divisors (1).

21045647191 is an equidigital number, since it uses as much as digits as its factorization.

21045647191 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 60480, while the sum is 40.

The spelling of 21045647191 in words is "twenty-one billion, forty-five million, six hundred forty-seven thousand, one hundred ninety-one".