221657943 has 8 divisors (see below), whose sum is σ = 318278128. Its totient is φ = 136404864.

The previous prime is 221657939. The next prime is 221657977. The reversal of 221657943 is 349756122.

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

It is not a de Polignac number, because 221657943 - 2² = 221657939 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (39), and also a Moran number because the ratio is a prime number: 5683537 = 221657943 / (2 + 2 + 1 + 6 + 5 + 7 + 9 + 4 + 3).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221657903) 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 7 ways as a sum of consecutive naturals, for example, 2841730 + ... + 2841807.

It is an arithmetic number, because the mean of its divisors is an integer number (39784766).

Almost surely, 2^221657943 is an apocalyptic number.

221657943 is a deficient number, since it is larger than the sum of its proper divisors (96620185).

221657943 is a wasteful number, since it uses less digits than its factorization.

221657943 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5683553.

The product of its digits is 90720, while the sum is 39.

The square root of 221657943 is about 14888.1813194225. The cubic root of 221657943 is about 605.1937480233.

The spelling of 221657943 in words is "two hundred twenty-one million, six hundred fifty-seven thousand, nine hundred forty-three".