145356221 has 2 divisors, whose sum is σ = 145356222. Its totient is φ = 145356220.

The previous prime is 145356217. The next prime is 145356223. The reversal of 145356221 is 122653541.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 81180100 + 64176121 = 9010^2 + 8011^2 .

It is an emirp because it is prime and its reverse (122653541) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 145356221 - 2² = 145356217 is a prime.

It is a super-2 number, since 2×145356221² = 42256861966801682, which contains 22 as substring.

Together with 145356223, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (145356223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 72678110 + 72678111.

It is an arithmetic number, because the mean of its divisors is an integer number (72678111).

Almost surely, 2^145356221 is an apocalyptic number.

It is an amenable number.

145356221 is a deficient number, since it is larger than the sum of its proper divisors (1).

145356221 is an equidigital number, since it uses as much as digits as its factorization.

145356221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7200, while the sum is 29.

The square root of 145356221 is about 12056.3767774568. The cubic root of 145356221 is about 525.7886511332.

The spelling of 145356221 in words is "one hundred forty-five million, three hundred fifty-six thousand, two hundred twenty-one".