26991001 has 8 divisors (see below), whose sum is σ = 28479680. Its totient is φ = 25509168.

The previous prime is 26990989. The next prime is 26991023. The reversal of 26991001 is 10019962.

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

It is a 7-Lehmer number, since φ(26991001) divides (26991001-1)⁷.

It is a cyclic number.

It is not a de Polignac number, because 26991001 - 2¹⁵ = 26958233 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (26991091) 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, 7795 + ... + 10711.

It is an arithmetic number, because the mean of its divisors is an integer number (3559960).

Almost surely, 2^26991001 is an apocalyptic number.

26991001 is the 3000-th hex number.

It is an amenable number.

26991001 is a deficient number, since it is larger than the sum of its proper divisors (1488679).

26991001 is a wasteful number, since it uses less digits than its factorization.

26991001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3423.

The product of its (nonzero) digits is 972, while the sum is 28.

The square root of 26991001 is about 5195.2864213631. The cubic root of 26991001 is about 299.9666666668.

The spelling of 26991001 in words is "twenty-six million, nine hundred ninety-one thousand, one".