20664023693 has 2 divisors, whose sum is σ = 20664023694. Its totient is φ = 20664023692.

The previous prime is 20664023671. The next prime is 20664023711. The reversal of 20664023693 is 39632046602.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18533555044 + 2130468649 = 136138^2 + 46157^2 .

It is a cyclic number.

It is not a de Polignac number, because 20664023693 - 2⁸ = 20664023437 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20664023693.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20664023663) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10332011846 + 10332011847.

It is an arithmetic number, because the mean of its divisors is an integer number (10332011847).

Almost surely, 2^20664023693 is an apocalyptic number.

It is an amenable number.

20664023693 is a deficient number, since it is larger than the sum of its proper divisors (1).

20664023693 is an equidigital number, since it uses as much as digits as its factorization.

20664023693 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 279936, while the sum is 41.

The spelling of 20664023693 in words is "twenty billion, six hundred sixty-four million, twenty-three thousand, six hundred ninety-three".