221434661 has 4 divisors (see below), whose sum is σ = 253068192. Its totient is φ = 189801132.

The previous prime is 221434657. The next prime is 221434679. The reversal of 221434661 is 166434122.

221434661 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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, and also an emirpimes, since its reverse is a distinct semiprime: 166434122 = 2 ⋅83217061.

It is a cyclic number.

It is not a de Polignac number, because 221434661 - 2² = 221434657 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 (221434361) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15816755 + ... + 15816768.

It is an arithmetic number, because the mean of its divisors is an integer number (63267048).

Almost surely, 2^221434661 is an apocalyptic number.

It is an amenable number.

221434661 is a deficient number, since it is larger than the sum of its proper divisors (31633531).

221434661 is an equidigital number, since it uses as much as digits as its factorization.

221434661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31633530.

The product of its digits is 6912, while the sum is 29.

The square root of 221434661 is about 14880.6807975979. The cubic root of 221434661 is about 604.9904704462.

Adding to 221434661 its reverse (166434122), we get a palindrome (387868783).

The spelling of 221434661 in words is "two hundred twenty-one million, four hundred thirty-four thousand, six hundred sixty-one".