20645818799 has 2 divisors, whose sum is σ = 20645818800. Its totient is φ = 20645818798.

The previous prime is 20645818723. The next prime is 20645818813. The reversal of 20645818799 is 99781854602.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20645818799 - 2²⁴ = 20629041583 is a prime.

It is a super-2 number, since 2×20645818799² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20645818499) 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 as a sum of consecutive naturals, namely, 10322909399 + 10322909400.

It is an arithmetic number, because the mean of its divisors is an integer number (10322909400).

Almost surely, 2^20645818799 is an apocalyptic number.

20645818799 is a deficient number, since it is larger than the sum of its proper divisors (1).

20645818799 is an equidigital number, since it uses as much as digits as its factorization.

20645818799 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8709120, while the sum is 59.

The spelling of 20645818799 in words is "twenty billion, six hundred forty-five million, eight hundred eighteen thousand, seven hundred ninety-nine".