2131555 has 4 divisors (see below), whose sum is σ = 2557872. Its totient is φ = 1705240.

The previous prime is 2131541. The next prime is 2131559. The reversal of 2131555 is 5551312.

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

It is not a de Polignac number, because 2131555 - 2⁷ = 2131427 is a prime.

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2131559) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 213151 + ... + 213160.

It is an arithmetic number, because the mean of its divisors is an integer number (639468).

2^2131555 is an apocalyptic number.

2131555 is a deficient number, since it is larger than the sum of its proper divisors (426317).

2131555 is an equidigital number, since it uses as much as digits as its factorization.

2131555 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 426316.

The product of its digits is 750, while the sum is 22.

The square root of 2131555 is about 1459.9845889598. The cubic root of 2131555 is about 128.6961379628.

Adding to 2131555 its reverse (5551312), we get a palindrome (7682867).

The spelling of 2131555 in words is "two million, one hundred thirty-one thousand, five hundred fifty-five".