27958820891 has 16 divisors (see below), whose sum is σ = 31886236800. Its totient is φ = 24349465728.

The previous prime is 27958820867. The next prime is 27958820969. The reversal of 27958820891 is 19802885972.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-27958820891 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 27958820891.

It is not an unprimeable number, because it can be changed into a prime (27958840891) 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, 992621 + ... + 1020398.

It is an arithmetic number, because the mean of its divisors is an integer number (1992889800).

Almost surely, 2^27958820891 is an apocalyptic number.

27958820891 is a deficient number, since it is larger than the sum of its proper divisors (3927415909).

27958820891 is a wasteful number, since it uses less digits than its factorization.

27958820891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2013098.

The product of its (nonzero) digits is 5806080, while the sum is 59.

The spelling of 27958820891 in words is "twenty-seven billion, nine hundred fifty-eight million, eight hundred twenty thousand, eight hundred ninety-one".