26999999991 has 12 divisors (see below), whose sum is σ = 39002522832. Its totient is φ = 17998835616.

The previous prime is 26999999987. The next prime is 26999999993. The reversal of 26999999991 is 19999999962.

It is not a de Polignac number, because 26999999991 - 2² = 26999999987 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 26999999991.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (26999999993) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 63870 + ... + 240996.

It is an arithmetic number, because the mean of its divisors is an integer number (3250210236).

Almost surely, 2^26999999991 is an apocalyptic number.

26999999991 is a deficient number, since it is larger than the sum of its proper divisors (12002522841).

26999999991 is a wasteful number, since it uses less digits than its factorization.

26999999991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 194070 (or 194067 counting only the distinct ones).

The product of its digits is 516560652, while the sum is 81.

Adding to 26999999991 its sum of digits (81), we get a palindrome (27000000072).

The spelling of 26999999991 in words is "twenty-six billion, nine hundred ninety-nine million, nine hundred ninety-nine thousand, nine hundred ninety-one".