2691391 has 4 divisors (see below), whose sum is σ = 2808432. Its totient is φ = 2574352.

The previous prime is 2691373. The next prime is 2691401. The reversal of 2691391 is 1931962.

2691391 = T₁₃₃₈ + T₁₃₃₉ + T₁₃₄₀.

2691391 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 2691391 - 2¹⁹ = 2167103 is a prime.

It is a Duffinian number.

2691391 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2691191) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 58486 + ... + 58531.

It is an arithmetic number, because the mean of its divisors is an integer number (702108).

2^2691391 is an apocalyptic number.

2691391 is the 1340-th centered triangular number.

2691391 is a deficient number, since it is larger than the sum of its proper divisors (117041).

2691391 is a wasteful number, since it uses less digits than its factorization.

2691391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 117040.

The product of its digits is 2916, while the sum is 31.

The square root of 2691391 is about 1640.5459457144. The cubic root of 2691391 is about 139.0995095116.

The spelling of 2691391 in words is "two million, six hundred ninety-one thousand, three hundred ninety-one".