2155455221 has 4 divisors (see below), whose sum is σ = 2164042944. Its totient is φ = 2146867500.

The previous prime is 2155455217. The next prime is 2155455227. The reversal of 2155455221 is 1225545512.

It is a happy number.

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 2155455221 - 2² = 2155455217 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2155455227) 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, 4293485 + ... + 4293986.

It is an arithmetic number, because the mean of its divisors is an integer number (541010736).

Almost surely, 2^2155455221 is an apocalyptic number.

It is an amenable number.

2155455221 is a deficient number, since it is larger than the sum of its proper divisors (8587723).

2155455221 is an equidigital number, since it uses as much as digits as its factorization.

2155455221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8587722.

The product of its digits is 20000, while the sum is 32.

The square root of 2155455221 is about 46426.8803711815. The cubic root of 2155455221 is about 1291.7535635709.

The spelling of 2155455221 in words is "two billion, one hundred fifty-five million, four hundred fifty-five thousand, two hundred twenty-one".