2161421 has 4 divisors (see below), whose sum is σ = 2275200. Its totient is φ = 2047644.

The previous prime is 2161417. The next prime is 2161427. The reversal of 2161421 is 1241612.

2161421 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 2161421 - 2² = 2161417 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 2161421.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2161427) 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 in 3 ways as a sum of consecutive naturals, for example, 56861 + ... + 56898.

It is an arithmetic number, because the mean of its divisors is an integer number (568800).

2^2161421 is an apocalyptic number.

It is an amenable number.

2161421 is a deficient number, since it is larger than the sum of its proper divisors (113779).

2161421 is a wasteful number, since it uses less digits than its factorization.

2161421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 113778.

The product of its digits is 96, while the sum is 17.

The square root of 2161421 is about 1470.1772002041. The cubic root of 2161421 is about 129.2944219630.

It can be divided in two parts, 216 and 1421, that multiplied together give a triangular number (306936 = T₇₈₃).

The spelling of 2161421 in words is "two million, one hundred sixty-one thousand, four hundred twenty-one".