145505491 has 2 divisors, whose sum is σ = 145505492. Its totient is φ = 145505490.

The previous prime is 145505489. The next prime is 145505501. The reversal of 145505491 is 194505541.

It is a happy number.

145505491 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is an emirp because it is prime and its reverse (194505541) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 145505491 - 2¹ = 145505489 is a prime.

It is a super-2 number, since 2×145505491² = 42343695822302162, which contains 22 as substring.

Together with 145505489, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (145505461) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 72752745 + 72752746.

It is an arithmetic number, because the mean of its divisors is an integer number (72752746).

Almost surely, 2^145505491 is an apocalyptic number.

145505491 is a deficient number, since it is larger than the sum of its proper divisors (1).

145505491 is an equidigital number, since it uses as much as digits as its factorization.

145505491 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 18000, while the sum is 34.

The square root of 145505491 is about 12062.5656889403. The cubic root of 145505491 is about 525.9685714715.

Subtracting 145505491 from its reverse (194505541), we obtain a triangular number (49000050 = T₉₈₉₉).

The spelling of 145505491 in words is "one hundred forty-five million, five hundred five thousand, four hundred ninety-one".