221020215 has 48 divisors (see below), whose sum is σ = 390533472. Its totient is φ = 106106112.

The previous prime is 221020211. The next prime is 221020237. The reversal of 221020215 is 512020122.

It is not a de Polignac number, because 221020215 - 2² = 221020211 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a junction number, because it is equal to n+sod(n) for n = 221020194 and 221020203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221020211) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 360249 + ... + 360861.

It is an arithmetic number, because the mean of its divisors is an integer number (8136114).

Almost surely, 2^221020215 is an apocalyptic number.

221020215 is a deficient number, since it is larger than the sum of its proper divisors (169513257).

221020215 is a wasteful number, since it uses less digits than its factorization.

221020215 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 720 (or 677 counting only the distinct ones).

The product of its (nonzero) digits is 80, while the sum is 15.

The square root of 221020215 is about 14866.7486357979. The cubic root of 221020215 is about 604.6127932398.

Adding to 221020215 its reverse (512020122), we get a palindrome (733040337).

The spelling of 221020215 in words is "two hundred twenty-one million, twenty thousand, two hundred fifteen".