145169021 has 2 divisors, whose sum is σ = 145169022. Its totient is φ = 145169020.

The previous prime is 145168999. The next prime is 145169023. The reversal of 145169021 is 120961541.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 127012900 + 18156121 = 11270^2 + 4261^2 .

It is an emirp because it is prime and its reverse (120961541) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-145169021 is a prime.

It is a Sophie Germain prime.

Together with 145169023, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (145169023) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 72584510 + 72584511.

It is an arithmetic number, because the mean of its divisors is an integer number (72584511).

Almost surely, 2^145169021 is an apocalyptic number.

It is an amenable number.

145169021 is a deficient number, since it is larger than the sum of its proper divisors (1).

145169021 is an equidigital number, since it uses as much as digits as its factorization.

145169021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2160, while the sum is 29.

The square root of 145169021 is about 12048.6107497919. The cubic root of 145169021 is about 525.5628382553.

The spelling of 145169021 in words is "one hundred forty-five million, one hundred sixty-nine thousand, twenty-one".