145018721 has 8 divisors (see below), whose sum is σ = 153932040. Its totient is φ = 136147968.

The previous prime is 145018691. The next prime is 145018733. The reversal of 145018721 is 127810541.

It can be written as a sum of positive squares in 4 ways, for example, as 115261696 + 29757025 = 10736^2 + 5455^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 145018721 - 2¹⁴ = 145002337 is a prime.

It is an alternating number because its digits alternate between odd and even.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (145018751) 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 7 ways as a sum of consecutive naturals, for example, 3476 + ... + 17381.

It is an arithmetic number, because the mean of its divisors is an integer number (19241505).

Almost surely, 2^145018721 is an apocalyptic number.

145018721 is the 6953-rd octagonal number.

It is an amenable number.

145018721 is a deficient number, since it is larger than the sum of its proper divisors (8913319).

145018721 is a wasteful number, since it uses less digits than its factorization.

145018721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21283.

The product of its (nonzero) digits is 2240, while the sum is 29.

The square root of 145018721 is about 12042.3719009172. The cubic root of 145018721 is about 525.3813960277.

The spelling of 145018721 in words is "one hundred forty-five million, eighteen thousand, seven hundred twenty-one".