145542209 has 4 divisors (see below), whose sum is σ = 145648980. Its totient is φ = 145435440.

The previous prime is 145542197. The next prime is 145542227. The reversal of 145542209 is 902245541.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 902245541 = 23 ⋅39228067.

It can be written as a sum of positive squares in 2 ways, for example, as 94633984 + 50908225 = 9728^2 + 7135^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-145542209 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (145542269) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 51314 + ... + 54075.

It is an arithmetic number, because the mean of its divisors is an integer number (36412245).

Almost surely, 2^145542209 is an apocalyptic number.

It is an amenable number.

145542209 is a deficient number, since it is larger than the sum of its proper divisors (106771).

145542209 is a wasteful number, since it uses less digits than its factorization.

145542209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 106770.

The product of its (nonzero) digits is 14400, while the sum is 32.

The square root of 145542209 is about 12064.0875742843. The cubic root of 145542209 is about 526.0128100992.

The spelling of 145542209 in words is "one hundred forty-five million, five hundred forty-two thousand, two hundred nine".