2205991 has 4 divisors (see below), whose sum is σ = 2277184. Its totient is φ = 2134800.

The previous prime is 2205989. The next prime is 2206021. The reversal of 2205991 is 1995022.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1995022 = 2 ⋅997511.

It is a cyclic number.

It is not a de Polignac number, because 2205991 - 2¹ = 2205989 is a prime.

It is a Duffinian number.

2205991 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2205911) 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, 35550 + ... + 35611.

It is an arithmetic number, because the mean of its divisors is an integer number (569296).

2^2205991 is an apocalyptic number.

2205991 is a deficient number, since it is larger than the sum of its proper divisors (71193).

2205991 is an equidigital number, since it uses as much as digits as its factorization.

2205991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 71192.

The product of its (nonzero) digits is 1620, while the sum is 28.

The square root of 2205991 is about 1485.2578900649. The cubic root of 2205991 is about 130.1770959150.

The spelling of 2205991 in words is "two million, two hundred five thousand, nine hundred ninety-one".