221430405 has 32 divisors (see below), whose sum is σ = 406713600. Its totient is φ = 100772352.

The previous prime is 221430403. The next prime is 221430409. The reversal of 221430405 is 504034122.

It is not a de Polignac number, because 221430405 - 2¹ = 221430403 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a zygodrome in base 6.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221430403) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 19441 + ... + 28649.

It is an arithmetic number, because the mean of its divisors is an integer number (12709800).

Almost surely, 2^221430405 is an apocalyptic number.

It is an amenable number.

221430405 is a deficient number, since it is larger than the sum of its proper divisors (185283195).

221430405 is a wasteful number, since it uses less digits than its factorization.

221430405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9453.

The product of its (nonzero) digits is 960, while the sum is 21.

The square root of 221430405 is about 14880.5377927009. The cubic root of 221430405 is about 604.9865944255.

Adding to 221430405 its reverse (504034122), we get a palindrome (725464527).

The spelling of 221430405 in words is "two hundred twenty-one million, four hundred thirty thousand, four hundred five".