145404221 has 4 divisors (see below), whose sum is σ = 145438944. Its totient is φ = 145369500.

The previous prime is 145404211. The next prime is 145404223. The reversal of 145404221 is 122404541.

145404221 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 a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 122404541 = 7 ⋅17486363.

It is a cyclic number.

It is not a de Polignac number, because 145404221 - 2¹⁰ = 145403197 is a prime.

It is a super-2 number, since 2×145404221² = 42284774969233682, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (145404223) 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, 10055 + ... + 19796.

It is an arithmetic number, because the mean of its divisors is an integer number (36359736).

Almost surely, 2^145404221 is an apocalyptic number.

It is an amenable number.

145404221 is a deficient number, since it is larger than the sum of its proper divisors (34723).

145404221 is an equidigital number, since it uses as much as digits as its factorization.

145404221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34722.

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

The square root of 145404221 is about 12058.3672609520. The cubic root of 145404221 is about 525.8465206383.

Adding to 145404221 its reverse (122404541), we get a palindrome (267808762).

The spelling of 145404221 in words is "one hundred forty-five million, four hundred four thousand, two hundred twenty-one".