20645755754609 has 2 divisors, whose sum is σ = 20645755754610. Its totient is φ = 20645755754608.

The previous prime is 20645755754599. The next prime is 20645755754621. The reversal of 20645755754609 is 90645755754602.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19892019242209 + 753736512400 = 4460047^2 + 868180^2 .

It is a cyclic number.

It is not a de Polignac number, because 20645755754609 - 2²⁸ = 20645487319153 is a prime.

It is not a weakly prime, because it can be changed into another prime (20645755754629) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10322877877304 + 10322877877305.

It is an arithmetic number, because the mean of its divisors is an integer number (10322877877305).

Almost surely, 2^{20645755754609} is an apocalyptic number.

It is an amenable number.

20645755754609 is a deficient number, since it is larger than the sum of its proper divisors (1).

20645755754609 is an equidigital number, since it uses as much as digits as its factorization.

20645755754609 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 317520000, while the sum is 65.

The spelling of 20645755754609 in words is "twenty trillion, six hundred forty-five billion, seven hundred fifty-five million, seven hundred fifty-four thousand, six hundred nine".