2155891 has 8 divisors (see below), whose sum is σ = 2226224. Its totient is φ = 2086560.

The previous prime is 2155883. The next prime is 2155931. The reversal of 2155891 is 1985512.

2155891 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 2155891 - 2³ = 2155883 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2155841) 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 7 ways as a sum of consecutive naturals, for example, 7645 + ... + 7921.

It is an arithmetic number, because the mean of its divisors is an integer number (278278).

2^2155891 is an apocalyptic number.

2155891 is a deficient number, since it is larger than the sum of its proper divisors (70333).

2155891 is a wasteful number, since it uses less digits than its factorization.

2155891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 501.

The product of its digits is 3600, while the sum is 31.

The square root of 2155891 is about 1468.2952700326. The cubic root of 2155891 is about 129.1840611099.

It can be divided in two parts, 21 and 55891, that multiplied together give a palindrome (1173711).

The spelling of 2155891 in words is "two million, one hundred fifty-five thousand, eight hundred ninety-one".