2155491 has 40 divisors (see below), whose sum is σ = 3659040. Its totient is φ = 1254528.

The previous prime is 2155487. The next prime is 2155499. The reversal of 2155491 is 1945512.

2155491 is a `hidden beast` number, since 21 + 554 + 91 = 666.

2155491 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 2155491 - 2² = 2155487 is a prime.

It is a super-2 number, since 2×2155491² = 9292282902162, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (2155499) 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 39 ways as a sum of consecutive naturals, for example, 24175 + ... + 24263.

It is an arithmetic number, because the mean of its divisors is an integer number (91476).

2^2155491 is an apocalyptic number.

2155491 is a deficient number, since it is larger than the sum of its proper divisors (1503549).

2155491 is a wasteful number, since it uses less digits than its factorization.

2155491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 137 (or 128 counting only the distinct ones).

The product of its digits is 1800, while the sum is 27.

The square root of 2155491 is about 1468.1590513292. The cubic root of 2155491 is about 129.1760710923.

The spelling of 2155491 in words is "two million, one hundred fifty-five thousand, four hundred ninety-one".