221215045 has 16 divisors (see below), whose sum is σ = 282040560. Its totient is φ = 166247424.

The previous prime is 221215031. The next prime is 221215051. The reversal of 221215045 is 540512122.

It can be written as a sum of positive squares in 8 ways, for example, as 2825761 + 218389284 = 1681^2 + 14778^2 .

It is a cyclic number.

It is not a de Polignac number, because 221215045 - 2⁹ = 221214533 is a prime.

It is a super-2 number, since 2×221215045² = 97872192268704050, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 15252 + ... + 25981.

It is an arithmetic number, because the mean of its divisors is an integer number (17627535).

Almost surely, 2^221215045 is an apocalyptic number.

It is an amenable number.

221215045 is a deficient number, since it is larger than the sum of its proper divisors (60825515).

221215045 is a wasteful number, since it uses less digits than its factorization.

221215045 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41304.

The product of its (nonzero) digits is 800, while the sum is 22.

The square root of 221215045 is about 14873.2997347596. The cubic root of 221215045 is about 604.7903970768.

Adding to 221215045 its reverse (540512122), we get a palindrome (761727167).

The spelling of 221215045 in words is "two hundred twenty-one million, two hundred fifteen thousand, forty-five".