26101991 has 4 divisors (see below), whose sum is σ = 27475800. Its totient is φ = 24728184.

The previous prime is 26101981. The next prime is 26101993. The reversal of 26101991 is 19910162.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 26101991 - 2¹⁴ = 26085607 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 (26101993) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 686876 + ... + 686913.

It is an arithmetic number, because the mean of its divisors is an integer number (6868950).

Almost surely, 2^26101991 is an apocalyptic number.

26101991 is a deficient number, since it is larger than the sum of its proper divisors (1373809).

26101991 is a wasteful number, since it uses less digits than its factorization.

26101991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1373808.

The product of its (nonzero) digits is 972, while the sum is 29.

The square root of 26101991 is about 5109.0107653048. The cubic root of 26101991 is about 296.6364705761.

The spelling of 26101991 in words is "twenty-six million, one hundred one thousand, nine hundred ninety-one".