210505221 has 24 divisors (see below), whose sum is σ = 314595840. Its totient is φ = 135496800.

The previous prime is 210505213. The next prime is 210505277. The reversal of 210505221 is 122505012.

It is not a de Polignac number, because 210505221 - 2³ = 210505213 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 210505194 and 210505203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (210505201) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 228600 + ... + 229518.

It is an arithmetic number, because the mean of its divisors is an integer number (13108160).

Almost surely, 2^210505221 is an apocalyptic number.

It is an amenable number.

210505221 is a deficient number, since it is larger than the sum of its proper divisors (104090619).

210505221 is a wasteful number, since it uses less digits than its factorization.

210505221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1777 (or 1774 counting only the distinct ones).

The product of its (nonzero) digits is 200, while the sum is 18.

The square root of 210505221 is about 14508.7980549734. The cubic root of 210505221 is about 594.8684792749.

The spelling of 210505221 in words is "two hundred ten million, five hundred five thousand, two hundred twenty-one".