26639981 has 8 divisors (see below), whose sum is σ = 27462528. Its totient is φ = 25830000.

The previous prime is 26639971. The next prime is 26639989. The reversal of 26639981 is 18993662.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 26639981 - 2¹⁰ = 26638957 is a prime.

It is a super-3 number, since 3×26639981³ (a number of 23 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (26639989) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1256 + ... + 7406.

It is an arithmetic number, because the mean of its divisors is an integer number (3432816).

Almost surely, 2^26639981 is an apocalyptic number.

It is an amenable number.

26639981 is a deficient number, since it is larger than the sum of its proper divisors (822547).

26639981 is an equidigital number, since it uses as much as digits as its factorization.

26639981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6283.

The product of its digits is 139968, while the sum is 44.

The square root of 26639981 is about 5161.3933196376. The cubic root of 26639981 is about 298.6606254480.

The spelling of 26639981 in words is "twenty-six million, six hundred thirty-nine thousand, nine hundred eighty-one".