221436 has 18 divisors (see below), whose sum is σ = 559832. Its totient is φ = 73800.

The previous prime is 221413. The next prime is 221447. The reversal of 221436 is 634122.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (18).

It is a hoax number, since the sum of its digits (18) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 221436.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 3040 + ... + 3111.

2²²¹⁴³⁶ is an apocalyptic number.

It is an amenable number.

221436 is an abundant number, since it is smaller than the sum of its proper divisors (338396).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

221436 is a wasteful number, since it uses less digits than its factorization.

221436 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6161 (or 6156 counting only the distinct ones).

The product of its digits is 288, while the sum is 18.

The square root of 221436 is about 470.5698672886. The cubic root of 221436 is about 60.4991689889.

Adding to 221436 its reverse (634122), we get a palindrome (855558).

Subtracting 221436 from its reverse (634122), we obtain a triangular number (412686 = T₉₀₈).

The spelling of 221436 in words is "two hundred twenty-one thousand, four hundred thirty-six".