221206413 has 4 divisors (see below), whose sum is σ = 294941888. Its totient is φ = 147470940.

The previous prime is 221206409. The next prime is 221206457. The reversal of 221206413 is 314602122.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 221206413 - 2² = 221206409 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 221206413.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221206213) 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 3 ways as a sum of consecutive naturals, for example, 36867733 + ... + 36867738.

It is an arithmetic number, because the mean of its divisors is an integer number (73735472).

Almost surely, 2^221206413 is an apocalyptic number.

It is an amenable number.

221206413 is a deficient number, since it is larger than the sum of its proper divisors (73735475).

221206413 is an equidigital number, since it uses as much as digits as its factorization.

221206413 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 73735474.

The product of its (nonzero) digits is 576, while the sum is 21.

The square root of 221206413 is about 14873.0095474991. The cubic root of 221206413 is about 604.7825304952.

Adding to 221206413 its reverse (314602122), we get a palindrome (535808535).

The spelling of 221206413 in words is "two hundred twenty-one million, two hundred six thousand, four hundred thirteen".