2121656 has 8 divisors (see below), whose sum is σ = 3978120. Its totient is φ = 1060824.

The previous prime is 2121653. The next prime is 2121661. The reversal of 2121656 is 6561212.

2121656 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (8).

It is an alternating number because its digits alternate between even and odd.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2121653) 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 as a sum of consecutive naturals, namely, 132596 + ... + 132611.

It is an arithmetic number, because the mean of its divisors is an integer number (497265).

2^2121656 is an apocalyptic number.

It is an amenable number.

2121656 is a deficient number, since it is larger than the sum of its proper divisors (1856464).

2121656 is a wasteful number, since it uses less digits than its factorization.

2121656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 265213 (or 265209 counting only the distinct ones).

The product of its digits is 720, while the sum is 23.

The square root of 2121656 is about 1456.5905395821. The cubic root of 2121656 is about 128.4966059655.

Adding to 2121656 its reverse (6561212), we get a palindrome (8682868).

The spelling of 2121656 in words is "two million, one hundred twenty-one thousand, six hundred fifty-six".