221993457 has 16 divisors (see below), whose sum is σ = 343823232. Its totient is φ = 124773120.

The previous prime is 221993437. The next prime is 221993479. The reversal of 221993457 is 754399122.

It is not a de Polignac number, because 221993457 - 2⁷ = 221993329 is a prime.

It is not an unprimeable number, because it can be changed into a prime (221993417) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 85368 + ... + 87929.

It is an arithmetic number, because the mean of its divisors is an integer number (21488952).

Almost surely, 2^221993457 is an apocalyptic number.

It is an amenable number.

221993457 is a deficient number, since it is larger than the sum of its proper divisors (121829775).

221993457 is a wasteful number, since it uses less digits than its factorization.

221993457 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 173368.

The product of its digits is 136080, while the sum is 42.

The square root of 221993457 is about 14899.4448554300. Note that the first 3 decimals coincide. The cubic root of 221993457 is about 605.4989459162.

The spelling of 221993457 in words is "two hundred twenty-one million, nine hundred ninety-three thousand, four hundred fifty-seven".