221646493 has 8 divisors (see below), whose sum is σ = 235045368. Its totient is φ = 208287744.

The previous prime is 221646487. The next prime is 221646517. The reversal of 221646493 is 394646122.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 25030009 + 196616484 = 5003^2 + 14022^2 .

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 221646493 - 2⁵ = 221646461 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221646433) 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, 1755 + ... + 21127.

It is an arithmetic number, because the mean of its divisors is an integer number (29380671).

Almost surely, 2^221646493 is an apocalyptic number.

It is an amenable number.

221646493 is a deficient number, since it is larger than the sum of its proper divisors (13398875).

221646493 is a wasteful number, since it uses less digits than its factorization.

221646493 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20063.

The product of its digits is 62208, while the sum is 37.

The square root of 221646493 is about 14887.7967812568. The cubic root of 221646493 is about 605.1833271805.

The spelling of 221646493 in words is "two hundred twenty-one million, six hundred forty-six thousand, four hundred ninety-three".