20788726717457 has 4 divisors (see below), whose sum is σ = 20789095570980. Its totient is φ = 20788357863936.

The previous prime is 20788726717439. The next prime is 20788726717463. The reversal of 20788726717457 is 75471762788702.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 2523907319761 + 18264819397696 = 1588681^2 + 4273736^2 .

It is a cyclic number.

It is not a de Polignac number, because 20788726717457 - 2¹⁴ = 20788726701073 is a prime.

It is a super-2 number, since 2×20788726717457² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20788726717477) 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 in 3 ways as a sum of consecutive naturals, for example, 184342208 + ... + 184454945.

It is an arithmetic number, because the mean of its divisors is an integer number (5197273892745).

Almost surely, 2^{20788726717457} is an apocalyptic number.

It is an amenable number.

20788726717457 is a deficient number, since it is larger than the sum of its proper divisors (368853523).

20788726717457 is an equidigital number, since it uses as much as digits as its factorization.

20788726717457 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 368853522.

The product of its (nonzero) digits is 516311040, while the sum is 71.

The spelling of 20788726717457 in words is "twenty trillion, seven hundred eighty-eight billion, seven hundred twenty-six million, seven hundred seventeen thousand, four hundred fifty-seven".