221791381 has 8 divisors (see below), whose sum is σ = 254487744. Its totient is φ = 189348000.

The previous prime is 221791321. The next prime is 221791387. The reversal of 221791381 is 183197122.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 221791381 - 2¹⁵ = 221758613 is a prime.

It is a super-2 number, since 2×221791381² = 98382833371774322, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221791387) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 61360 + ... + 64873.

It is an arithmetic number, because the mean of its divisors is an integer number (31810968).

Almost surely, 2^221791381 is an apocalyptic number.

It is an amenable number.

221791381 is a deficient number, since it is larger than the sum of its proper divisors (32696363).

221791381 is a wasteful number, since it uses less digits than its factorization.

221791381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 126491.

The product of its digits is 6048, while the sum is 34.

The square root of 221791381 is about 14892.6619850180. The cubic root of 221791381 is about 605.3151657999.

The spelling of 221791381 in words is "two hundred twenty-one million, seven hundred ninety-one thousand, three hundred eighty-one".