221585791441 has 9 divisors (see below), whose sum is σ = 257766896649. Its totient is φ = 189927854004.

The previous prime is 221585791433. The next prime is 221585791451. The reversal of 221585791441 is 144197585122.

The square root of 221585791441 is 470729.

It is a perfect power (a square), and thus also a powerful number.

It is not a de Polignac number, because 221585791441 - 2³ = 221585791433 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (49).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221585791451) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 3261480 + ... + 3328726.

Almost surely, 2^221585791441 is an apocalyptic number.

221585791441 is the 470729-th square number.

221585791441 is the 235365-th centered octagonal number.

It is an amenable number.

221585791441 is a deficient number, since it is larger than the sum of its proper divisors (36181105208).

221585791441 is an frugal number, since it uses more digits than its factorization.

221585791441 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 134508 (or 67254 counting only the distinct ones).

The product of its digits is 806400, while the sum is 49.

Multiplying 221585791441 by its sum of digits (49), we get a square (10857703780609 = 3295103²).

221585791441 divided by its sum of digits (49) gives a square (4522159009 = 67247²).

The spelling of 221585791441 in words is "two hundred twenty-one billion, five hundred eighty-five million, seven hundred ninety-one thousand, four hundred forty-one".