145212491 has 4 divisors (see below), whose sum is σ = 145267992. Its totient is φ = 145156992.

The previous prime is 145212481. The next prime is 145212503. The reversal of 145212491 is 194212541.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 194212541 = 4001 ⋅48541.

It is a cyclic number.

It is not a de Polignac number, because 145212491 - 2⁶ = 145212427 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (145212451) 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 in 3 ways as a sum of consecutive naturals, for example, 23621 + ... + 29126.

It is an arithmetic number, because the mean of its divisors is an integer number (36316998).

Almost surely, 2^145212491 is an apocalyptic number.

145212491 is a deficient number, since it is larger than the sum of its proper divisors (55501).

145212491 is an equidigital number, since it uses as much as digits as its factorization.

145212491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55500.

The product of its digits is 2880, while the sum is 29.

The square root of 145212491 is about 12050.4145571843. The cubic root of 145212491 is about 525.6152919088.

Subtracting 145212491 from its reverse (194212541), we obtain a triangular number (49000050 = T₉₈₉₉).

The spelling of 145212491 in words is "one hundred forty-five million, two hundred twelve thousand, four hundred ninety-one".