27805601991 has 16 divisors (see below), whose sum is σ = 39509167104. Its totient is φ = 17353848864.

The previous prime is 27805601983. The next prime is 27805602023. The reversal of 27805601991 is 19910650872.

It is not a de Polignac number, because 27805601991 - 2³ = 27805601983 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 27805601991.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (27805601921) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4283776 + ... + 4290261.

It is an arithmetic number, because the mean of its divisors is an integer number (2469322944).

Almost surely, 2^27805601991 is an apocalyptic number.

27805601991 is a deficient number, since it is larger than the sum of its proper divisors (11703565113).

27805601991 is a wasteful number, since it uses less digits than its factorization.

27805601991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8574110.

The product of its (nonzero) digits is 272160, while the sum is 48.

The spelling of 27805601991 in words is "twenty-seven billion, eight hundred five million, six hundred one thousand, nine hundred ninety-one".