20645184391567 has 2 divisors, whose sum is σ = 20645184391568. Its totient is φ = 20645184391566.

The previous prime is 20645184391511. The next prime is 20645184391577. The reversal of 20645184391567 is 76519348154602.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20645184391567 - 2²³ = 20645176002959 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20645184391577) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10322592195783 + 10322592195784.

It is an arithmetic number, because the mean of its divisors is an integer number (10322592195784).

It is a 1-persistent number, because it is pandigital, but 2⋅20645184391567 = 41290368783134 is not.

Almost surely, 2^{20645184391567} is an apocalyptic number.

20645184391567 is a deficient number, since it is larger than the sum of its proper divisors (1).

20645184391567 is an equidigital number, since it uses as much as digits as its factorization.

20645184391567 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 43545600, while the sum is 61.

The spelling of 20645184391567 in words is "twenty trillion, six hundred forty-five billion, one hundred eighty-four million, three hundred ninety-one thousand, five hundred sixty-seven".