145505221 has 2 divisors, whose sum is σ = 145505222. Its totient is φ = 145505220.

The previous prime is 145505207. The next prime is 145505231. The reversal of 145505221 is 122505541.

145505221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 73017025 + 72488196 = 8545^2 + 8514^2 .

It is a cyclic number.

It is not a de Polignac number, because 145505221 - 2⁵ = 145505189 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (145505231) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 72752610 + 72752611.

It is an arithmetic number, because the mean of its divisors is an integer number (72752611).

Almost surely, 2^145505221 is an apocalyptic number.

It is an amenable number.

145505221 is a deficient number, since it is larger than the sum of its proper divisors (1).

145505221 is an equidigital number, since it uses as much as digits as its factorization.

145505221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2000, while the sum is 25.

The square root of 145505221 is about 12062.5544972862. The cubic root of 145505221 is about 525.9682461422.

The spelling of 145505221 in words is "one hundred forty-five million, five hundred five thousand, two hundred twenty-one".