221504421 has 8 divisors (see below), whose sum is σ = 308180160. Its totient is φ = 141249152.

The previous prime is 221504401. The next prime is 221504429. The reversal of 221504421 is 124405122.

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 221504421 - 2⁵ = 221504389 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221504429) 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, 1605036 + ... + 1605173.

It is an arithmetic number, because the mean of its divisors is an integer number (38522520).

Almost surely, 2^221504421 is an apocalyptic number.

It is an amenable number.

221504421 is a deficient number, since it is larger than the sum of its proper divisors (86675739).

221504421 is a wasteful number, since it uses less digits than its factorization.

221504421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3210235.

The product of its (nonzero) digits is 640, while the sum is 21.

The square root of 221504421 is about 14883.0245917958. The cubic root of 221504421 is about 605.0539951354.

Adding to 221504421 its reverse (124405122), we get a palindrome (345909543).

The spelling of 221504421 in words is "two hundred twenty-one million, five hundred four thousand, four hundred twenty-one".