145681309 has 4 divisors (see below), whose sum is σ = 145705504. Its totient is φ = 145657116.

The previous prime is 145681271. The next prime is 145681337. The reversal of 145681309 is 903186541.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-145681309 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (145681339) 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 in 3 ways as a sum of consecutive naturals, for example, 4834 + ... + 17740.

It is an arithmetic number, because the mean of its divisors is an integer number (36426376).

Almost surely, 2^145681309 is an apocalyptic number.

It is an amenable number.

145681309 is a deficient number, since it is larger than the sum of its proper divisors (24195).

145681309 is a wasteful number, since it uses less digits than its factorization.

145681309 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24194.

The product of its (nonzero) digits is 25920, while the sum is 37.

The square root of 145681309 is about 12069.8512418339. The cubic root of 145681309 is about 526.1803332869.

The spelling of 145681309 in words is "one hundred forty-five million, six hundred eighty-one thousand, three hundred nine".