221322451 has 4 divisors (see below), whose sum is σ = 252939952. Its totient is φ = 189704952.

The previous prime is 221322449. The next prime is 221322467. The reversal of 221322451 is 154223122.

It is a happy number.

221322451 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 an emirpimes, since its reverse is a distinct semiprime: 154223122 = 2 ⋅77111561.

It is a cyclic number.

It is not a de Polignac number, because 221322451 - 2¹ = 221322449 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221322401) 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, 15808740 + ... + 15808753.

It is an arithmetic number, because the mean of its divisors is an integer number (63234988).

Almost surely, 2^221322451 is an apocalyptic number.

221322451 is a deficient number, since it is larger than the sum of its proper divisors (31617501).

221322451 is an equidigital number, since it uses as much as digits as its factorization.

221322451 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31617500.

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

The square root of 221322451 is about 14876.9099950225. The cubic root of 221322451 is about 604.8882620408. Note that the first 3 decimals are identical.

Adding to 221322451 its reverse (154223122), we get a palindrome (375545573).

The spelling of 221322451 in words is "two hundred twenty-one million, three hundred twenty-two thousand, four hundred fifty-one".