20508866139 has 4 divisors (see below), whose sum is σ = 27345154856. Its totient is φ = 13672577424.

The previous prime is 20508866111. The next prime is 20508866219. The reversal of 20508866139 is 93166880502.

It is a happy number.

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

It is not a de Polignac number, because 20508866139 - 2¹² = 20508862043 is a prime.

It is a super-2 number, since 2×20508866139² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20508866239) 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, 3418144354 + ... + 3418144359.

It is an arithmetic number, because the mean of its divisors is an integer number (6836288714).

Almost surely, 2^20508866139 is an apocalyptic number.

20508866139 is a deficient number, since it is larger than the sum of its proper divisors (6836288717).

20508866139 is an equidigital number, since it uses as much as digits as its factorization.

20508866139 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6836288716.

The product of its (nonzero) digits is 622080, while the sum is 48.

The spelling of 20508866139 in words is "twenty billion, five hundred eight million, eight hundred sixty-six thousand, one hundred thirty-nine".