2121 has 8 divisors (see below), whose sum is σ = 3264. Its totient is φ = 1200.

The previous prime is 2113. The next prime is 2129. The reversal of 2121 is 1212.

It is a happy number.

2121 is an esthetic number in base 10, because in such base its adjacent digits differ by 1.

It is an interprime number because it is at equal distance from previous prime (2113) and next prime (2129).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 2121 - 2^{3} = 2113 is a prime.

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

2121 is an undulating number in base 10.

It is a Curzon number.

2121 is a lucky number.

It is a plaindrome in base 12.

It is a nialpdrome in base 8, base 13 and base 15.

It is not an unprimeable number, because it can be changed into a prime (2129) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 30 + ... + 71.

It is an arithmetic number, because the mean of its divisors is an integer number (408).

2121 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

2121 is a deficient number, since it is larger than the sum of its proper divisors (1143).

2121 is a wasteful number, since it uses less digits than its factorization.

2121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 111.

The product of its digits is 4, while the sum is 6.

The square root of 2121 is about 46.0543157587. The cubic root of 2121 is about 12.8483361207.

Adding to 2121 its reverse (1212), we get a palindrome (3333).

Subtracting from 2121 its reverse (1212), we obtain a palindrome (909).

It can be divided in two parts, 2 and 121, that multiplied together give a palindrome (242).

The spelling of 2121 in words is "two thousand, one hundred twenty-one", and thus it is an iban number.

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