2161966 has 4 divisors (see below), whose sum is σ = 3242952. Its totient is φ = 1080982.

The previous prime is 2161963. The next prime is 2161967. The reversal of 2161966 is 6691612.

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

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2161963) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 540490 + ... + 540493.

It is an arithmetic number, because the mean of its divisors is an integer number (810738).

2^2161966 is an apocalyptic number.

2161966 is a deficient number, since it is larger than the sum of its proper divisors (1080986).

2161966 is a wasteful number, since it uses less digits than its factorization.

2161966 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1080985.

The product of its digits is 3888, while the sum is 31.

The square root of 2161966 is about 1470.3625403281. The cubic root of 2161966 is about 129.3052881999.

The spelling of 2161966 in words is "two million, one hundred sixty-one thousand, nine hundred sixty-six".