2121961 has 4 divisors (see below), whose sum is σ = 2162052. Its totient is φ = 2081872.

The previous prime is 2121943. The next prime is 2121967. The reversal of 2121961 is 1691212.

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

It can be written as a sum of positive squares in 2 ways, for example, as 1587600 + 534361 = 1260^2 + 731^2 .

It is a cyclic number.

It is not a de Polignac number, because 2121961 - 2¹¹ = 2119913 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 (2121967) 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, 19966 + ... + 20071.

It is an arithmetic number, because the mean of its divisors is an integer number (540513).

2^2121961 is an apocalyptic number.

It is an amenable number.

2121961 is a deficient number, since it is larger than the sum of its proper divisors (40091).

2121961 is an equidigital number, since it uses as much as digits as its factorization.

2121961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40090.

The product of its digits is 216, while the sum is 22.

The square root of 2121961 is about 1456.6952323667. The cubic root of 2121961 is about 128.5027630407.

The spelling of 2121961 in words is "two million, one hundred twenty-one thousand, nine hundred sixty-one".