26991864 has 24 divisors (see below), whose sum is σ = 73103160. Its totient is φ = 8997264.

The previous prime is 26991863. The next prime is 26991883. The reversal of 26991864 is 46819962.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (24).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (26991863) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 187372 + ... + 187515.

It is an arithmetic number, because the mean of its divisors is an integer number (3045965).

Almost surely, 2^26991864 is an apocalyptic number.

26991864 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

26991864 is an abundant number, since it is smaller than the sum of its proper divisors (46111296).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

26991864 is a wasteful number, since it uses less digits than its factorization.

26991864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 374899 (or 374892 counting only the distinct ones).

The product of its digits is 186624, while the sum is 45.

The square root of 26991864 is about 5195.3694767552. The cubic root of 26991864 is about 299.9698636394.

The spelling of 26991864 in words is "twenty-six million, nine hundred ninety-one thousand, eight hundred sixty-four".