2131556 has 24 divisors (see below), whose sum is σ = 4294080. Its totient is φ = 906912.

The previous prime is 2131541. The next prime is 2131559. The reversal of 2131556 is 6551312.

It is a super-2 number, since 2×2131556² = 9087061962272, which contains 22 as substring.

It is an Ulam number.

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

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7391 + ... + 7673.

It is an arithmetic number, because the mean of its divisors is an integer number (178920).

2^2131556 is an apocalyptic number.

It is an amenable number.

2131556 is an abundant number, since it is smaller than the sum of its proper divisors (2162524).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

2131556 is a wasteful number, since it uses less digits than its factorization.

2131556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 563 (or 561 counting only the distinct ones).

The product of its digits is 900, while the sum is 23.

The square root of 2131556 is about 1459.9849314291. The cubic root of 2131556 is about 128.6961580884.

Adding to 2131556 its reverse (6551312), we get a palindrome (8682868).

The spelling of 2131556 in words is "two million, one hundred thirty-one thousand, five hundred fifty-six".