2155969 has 4 divisors (see below), whose sum is σ = 2171844. Its totient is φ = 2140096.

The previous prime is 2155963. The next prime is 2155999. The reversal of 2155969 is 9695512.

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 1658944 + 497025 = 1288^2 + 705^2 .

It is a cyclic number.

It is not a de Polignac number, because 2155969 - 2³ = 2155961 is a prime.

It is a super-2 number, since 2×2155969² = 9296404657922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2155961) 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, 7732 + ... + 8005.

It is an arithmetic number, because the mean of its divisors is an integer number (542961).

2^2155969 is an apocalyptic number.

It is an amenable number.

2155969 is a deficient number, since it is larger than the sum of its proper divisors (15875).

2155969 is a wasteful number, since it uses less digits than its factorization.

2155969 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15874.

The product of its digits is 24300, while the sum is 37.

The square root of 2155969 is about 1468.3218312073. The cubic root of 2155969 is about 129.1856190481.

The spelling of 2155969 in words is "two million, one hundred fifty-five thousand, nine hundred sixty-nine".