26400991 has 8 divisors (see below), whose sum is σ = 27496800. Its totient is φ = 25317600.

The previous prime is 26400989. The next prime is 26401003. The reversal of 26400991 is 19900462.

It is a happy number.

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 26400991 - 2¹ = 26400989 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (26400971) 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, 1365 + ... + 7393.

It is an arithmetic number, because the mean of its divisors is an integer number (3437100).

Almost surely, 2^26400991 is an apocalyptic number.

26400991 is a deficient number, since it is larger than the sum of its proper divisors (1095809).

26400991 is a wasteful number, since it uses less digits than its factorization.

26400991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6209.

The product of its (nonzero) digits is 3888, while the sum is 31.

The square root of 26400991 is about 5138.1894671178. The cubic root of 26400991 is about 297.7648363176.

The spelling of 26400991 in words is "twenty-six million, four hundred thousand, nine hundred ninety-one".