221720406215 has 32 divisors (see below), whose sum is σ = 331864266240. Its totient is φ = 138153859200.

The previous prime is 221720406199. The next prime is 221720406227. The reversal of 221720406215 is 512604027122.

It is not a de Polignac number, because 221720406215 - 2⁴ = 221720406199 is a prime.

It is a super-2 number, since 2×221720406215² (a number of 23 digits) 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 31 ways as a sum of consecutive naturals, for example, 746660 + ... + 1000470.

It is an arithmetic number, because the mean of its divisors is an integer number (10370758320).

Almost surely, 2^221720406215 is an apocalyptic number.

221720406215 is a deficient number, since it is larger than the sum of its proper divisors (110143860025).

221720406215 is a wasteful number, since it uses less digits than its factorization.

221720406215 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 256103.

The product of its (nonzero) digits is 13440, while the sum is 32.

The spelling of 221720406215 in words is "two hundred twenty-one billion, seven hundred twenty million, four hundred six thousand, two hundred fifteen".