221445401 has 4 divisors (see below), whose sum is σ = 221476404. Its totient is φ = 221414400.

The previous prime is 221445391. The next prime is 221445457. The reversal of 221445401 is 104544122.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 104544122 = 2 ⋅52272061.

It can be written as a sum of positive squares in 2 ways, for example, as 3115225 + 218330176 = 1765^2 + 14776^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-221445401 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221445491) 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, 1241 + ... + 21081.

It is an arithmetic number, because the mean of its divisors is an integer number (55369101).

Almost surely, 2^221445401 is an apocalyptic number.

It is an amenable number.

221445401 is a deficient number, since it is larger than the sum of its proper divisors (31003).

221445401 is a wasteful number, since it uses less digits than its factorization.

221445401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31002.

The product of its (nonzero) digits is 1280, while the sum is 23.

The square root of 221445401 is about 14881.0416638084. The cubic root of 221445401 is about 605.0002513488. Note that the first 3 decimals are identical.

Adding to 221445401 its reverse (104544122), we get a palindrome (325989523).

The spelling of 221445401 in words is "two hundred twenty-one million, four hundred forty-five thousand, four hundred one".