27798577781 has 8 divisors (see below), whose sum is σ = 30746036664. Its totient is φ = 24966705600.

The previous prime is 27798577759. The next prime is 27798577783. The reversal of 27798577781 is 18777589772.

It can be written as a sum of positive squares in 4 ways, for example, as 38019556 + 27760558225 = 6166^2 + 166615^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 27798577781 - 2²⁶ = 27731468917 is a prime.

It is a super-2 number, since 2×27798577781² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (27798577783) 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 7 ways as a sum of consecutive naturals, for example, 28896170 + ... + 28897131.

It is an arithmetic number, because the mean of its divisors is an integer number (3843254583).

Almost surely, 2^27798577781 is an apocalyptic number.

It is an amenable number.

27798577781 is a deficient number, since it is larger than the sum of its proper divisors (2947458883).

27798577781 is a wasteful number, since it uses less digits than its factorization.

27798577781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 57793351.

The product of its digits is 96808320, while the sum is 68.

The spelling of 27798577781 in words is "twenty-seven billion, seven hundred ninety-eight million, five hundred seventy-seven thousand, seven hundred eighty-one".