221215715 has 16 divisors (see below), whose sum is σ = 305206272. Its totient is φ = 150778464.

The previous prime is 221215703. The next prime is 221215751. The reversal of 221215715 is 517512122.

It is a cyclic number.

It is not a de Polignac number, because 221215715 - 2¹⁰ = 221214691 is a prime.

It is a super-2 number, since 2×221215715² = 97872785125922450, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13079 + ... + 24768.

It is an arithmetic number, because the mean of its divisors is an integer number (19075392).

Almost surely, 2^221215715 is an apocalyptic number.

221215715 is a deficient number, since it is larger than the sum of its proper divisors (83990557).

221215715 is a wasteful number, since it uses less digits than its factorization.

221215715 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38026.

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

The square root of 221215715 is about 14873.3222583255. The cubic root of 221215715 is about 604.7910076579.

Adding to 221215715 its reverse (517512122), we get a palindrome (738727837).

The spelling of 221215715 in words is "two hundred twenty-one million, two hundred fifteen thousand, seven hundred fifteen".