20787454818737 has 4 divisors (see below), whose sum is σ = 21504263605620. Its totient is φ = 20070646031856.

The previous prime is 20787454818719. The next prime is 20787454818803. The reversal of 20787454818737 is 73781845478702.

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 5286729905521 + 15500724913216 = 2299289^2 + 3937096^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20787454818737 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20787454818937) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 358404393398 + ... + 358404393455.

It is an arithmetic number, because the mean of its divisors is an integer number (5376065901405).

Almost surely, 2^{20787454818737} is an apocalyptic number.

It is an amenable number.

20787454818737 is a deficient number, since it is larger than the sum of its proper divisors (716808786883).

20787454818737 is an equidigital number, since it uses as much as digits as its factorization.

20787454818737 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 716808786882.

The product of its (nonzero) digits is 590069760, while the sum is 71.

The spelling of 20787454818737 in words is "twenty trillion, seven hundred eighty-seven billion, four hundred fifty-four million, eight hundred eighteen thousand, seven hundred thirty-seven".