27806951138 has 18 divisors (see below), whose sum is σ = 42427362627. Its totient is φ = 13668474960.

The previous prime is 27806951093. The next prime is 27806951167. The reversal of 27806951138 is 83115960872.

It can be written as a sum of positive squares in 5 ways, for example, as 3568509169 + 24238441969 = 59737^2 + 155687^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=117913.

It is a super-2 number, since 2×27806951138² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is an unprimeable number.

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 8 ways as a sum of consecutive naturals, for example, 14384420 + ... + 14386352.

Almost surely, 2^27806951138 is an apocalyptic number.

27806951138 is a deficient number, since it is larger than the sum of its proper divisors (14620411489).

27806951138 is an frugal number, since it uses more digits than its factorization.

27806951138 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3990 (or 1996 counting only the distinct ones).

The product of its (nonzero) digits is 725760, while the sum is 50.

Multiplying 27806951138 by its sum of digits (50), we get a square (1390347556900 = 1179130²).

The spelling of 27806951138 in words is "twenty-seven billion, eight hundred six million, nine hundred fifty-one thousand, one hundred thirty-eight".