2161399 has 4 divisors (see below), whose sum is σ = 2235960. Its totient is φ = 2086840.

The previous prime is 2161373. The next prime is 2161409. The reversal of 2161399 is 9931612.

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

It is not a de Polignac number, because 2161399 - 2¹¹ = 2159351 is a prime.

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 Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 2161399.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2161319) 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, 37237 + ... + 37294.

It is an arithmetic number, because the mean of its divisors is an integer number (558990).

2^2161399 is an apocalyptic number.

2161399 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

2161399 is a deficient number, since it is larger than the sum of its proper divisors (74561).

2161399 is an equidigital number, since it uses as much as digits as its factorization.

2161399 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 74560.

The product of its digits is 2916, while the sum is 31.

The square root of 2161399 is about 1470.1697180938. The cubic root of 2161399 is about 129.2939832875.

It can be divided in two parts, 21613 and 99, that added together give a palindrome (21712).

The spelling of 2161399 in words is "two million, one hundred sixty-one thousand, three hundred ninety-nine".