221290928391 has 16 divisors (see below), whose sum is σ = 320897132640. Its totient is φ = 134830723200.

The previous prime is 221290928381. The next prime is 221290928471. The reversal of 221290928391 is 193829092122.

It is not a de Polignac number, because 221290928391 - 2¹⁰ = 221290927367 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 221290928391.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221290928351) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 28085796 + ... + 28093673.

It is an arithmetic number, because the mean of its divisors is an integer number (20056070790).

Almost surely, 2^221290928391 is an apocalyptic number.

221290928391 is a deficient number, since it is larger than the sum of its proper divisors (99606204249).

221290928391 is a wasteful number, since it uses less digits than its factorization.

221290928391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56179586.

The product of its (nonzero) digits is 279936, while the sum is 48.

The spelling of 221290928391 in words is "two hundred twenty-one billion, two hundred ninety million, nine hundred twenty-eight thousand, three hundred ninety-one".