145313221 has 2 divisors, whose sum is σ = 145313222. Its totient is φ = 145313220.

The previous prime is 145313173. The next prime is 145313261. The reversal of 145313221 is 122313541.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 129072321 + 16240900 = 11361^2 + 4030^2 .

It is a cyclic number.

It is not a de Polignac number, because 145313221 - 2²⁵ = 111758789 is a prime.

It is a super-2 number, since 2×145313221² = 42231864394789682, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 145313192 and 145313201.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (145313261) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 72656610 + 72656611.

It is an arithmetic number, because the mean of its divisors is an integer number (72656611).

Almost surely, 2^145313221 is an apocalyptic number.

It is an amenable number.

145313221 is a deficient number, since it is larger than the sum of its proper divisors (1).

145313221 is an equidigital number, since it uses as much as digits as its factorization.

145313221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 720, while the sum is 22.

The square root of 145313221 is about 12054.5933568910. The cubic root of 145313221 is about 525.7367988822.

Adding to 145313221 its reverse (122313541), we get a palindrome (267626762).

The spelling of 145313221 in words is "one hundred forty-five million, three hundred thirteen thousand, two hundred twenty-one".