2155107221 has 4 divisors (see below), whose sum is σ = 2281878252. Its totient is φ = 2028336192.

The previous prime is 2155107209. The next prime is 2155107257. The reversal of 2155107221 is 1227015512.

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 1796572996 + 358534225 = 42386^2 + 18935^2 .

It is a cyclic number.

It is not a de Polignac number, because 2155107221 - 2¹⁰ = 2155106197 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 (2055107221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 63385490 + ... + 63385523.

It is an arithmetic number, because the mean of its divisors is an integer number (570469563).

Almost surely, 2^2155107221 is an apocalyptic number.

It is an amenable number.

2155107221 is a deficient number, since it is larger than the sum of its proper divisors (126771031).

2155107221 is a wasteful number, since it uses less digits than its factorization.

2155107221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 126771030.

The product of its (nonzero) digits is 1400, while the sum is 26.

The square root of 2155107221 is about 46423.1323910828. The cubic root of 2155107221 is about 1291.6840416079.

The spelling of 2155107221 in words is "two billion, one hundred fifty-five million, one hundred seven thousand, two hundred twenty-one".