20505560036639 has 4 divisors (see below), whose sum is σ = 20595103967160. Its totient is φ = 20416016106120.

The previous prime is 20505560036617. The next prime is 20505560036641. The reversal of 20505560036639 is 93663006550502.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20505560036639 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20505560036669) 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, 44771964917 + ... + 44771965374.

It is an arithmetic number, because the mean of its divisors is an integer number (5148775991790).

Almost surely, 2^{20505560036639} is an apocalyptic number.

20505560036639 is a deficient number, since it is larger than the sum of its proper divisors (89543930521).

20505560036639 is an equidigital number, since it uses as much as digits as its factorization.

20505560036639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 89543930520.

The product of its (nonzero) digits is 4374000, while the sum is 50.

The spelling of 20505560036639 in words is "twenty trillion, five hundred five billion, five hundred sixty million, thirty-six thousand, six hundred thirty-nine".