27780861667 has 4 divisors (see below), whose sum is σ = 29917851040. Its totient is φ = 25643872296.

The previous prime is 27780861649. The next prime is 27780861671. The reversal of 27780861667 is 76616808772.

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

It is a cyclic number.

It is not a de Polignac number, because 27780861667 - 2¹⁹ = 27780337379 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (27780861697) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1068494667 + ... + 1068494692.

It is an arithmetic number, because the mean of its divisors is an integer number (7479462760).

Almost surely, 2^27780861667 is an apocalyptic number.

27780861667 is a deficient number, since it is larger than the sum of its proper divisors (2136989373).

27780861667 is a wasteful number, since it uses less digits than its factorization.

27780861667 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2136989372.

The product of its (nonzero) digits is 9483264, while the sum is 58.

The spelling of 27780861667 in words is "twenty-seven billion, seven hundred eighty million, eight hundred sixty-one thousand, six hundred sixty-seven".