20687931863 has 2 divisors, whose sum is σ = 20687931864. Its totient is φ = 20687931862.

The previous prime is 20687931851. The next prime is 20687931893. The reversal of 20687931863 is 36813978602.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20687931863 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20687931893) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10343965931 + 10343965932.

It is an arithmetic number, because the mean of its divisors is an integer number (10343965932).

Almost surely, 2^20687931863 is an apocalyptic number.

20687931863 is a deficient number, since it is larger than the sum of its proper divisors (1).

20687931863 is an equidigital number, since it uses as much as digits as its factorization.

20687931863 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2612736, while the sum is 53.

The spelling of 20687931863 in words is "twenty billion, six hundred eighty-seven million, nine hundred thirty-one thousand, eight hundred sixty-three".