221421523 has 8 divisors (see below), whose sum is σ = 225145440. Its totient is φ = 217714560.

The previous prime is 221421517. The next prime is 221421539. The reversal of 221421523 is 325124122.

It is a happy number.

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 221421523 - 2¹³ = 221413331 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 221421494 and 221421503.

It is not an unprimeable number, because it can be changed into a prime (221424523) 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 7 ways as a sum of consecutive naturals, for example, 23611 + ... + 31627.

It is an arithmetic number, because the mean of its divisors is an integer number (28143180).

Almost surely, 2^221421523 is an apocalyptic number.

221421523 is a deficient number, since it is larger than the sum of its proper divisors (3723917).

221421523 is an equidigital number, since it uses as much as digits as its factorization.

221421523 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8477.

The product of its digits is 960, while the sum is 22.

The square root of 221421523 is about 14880.2393461933. The cubic root of 221421523 is about 604.9785052582.

Adding to 221421523 its reverse (325124122), we get a palindrome (546545645).

The spelling of 221421523 in words is "two hundred twenty-one million, four hundred twenty-one thousand, five hundred twenty-three".