20178145 has 8 divisors (see below), whose sum is σ = 26076456. Its totient is φ = 14900736.

The previous prime is 20178143. The next prime is 20178157. The reversal of 20178145 is 54187102.

It can be written as a sum of positive squares in 4 ways, for example, as 3013696 + 17164449 = 1736^2 + 4143^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 20178145 - 2¹ = 20178143 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20178143) 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, 155152 + ... + 155281.

It is an arithmetic number, because the mean of its divisors is an integer number (3259557).

Almost surely, 2^20178145 is an apocalyptic number.

It is an amenable number.

20178145 is a deficient number, since it is larger than the sum of its proper divisors (5898311).

20178145 is a wasteful number, since it uses less digits than its factorization.

20178145 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 310451.

The product of its (nonzero) digits is 2240, while the sum is 28.

The square root of 20178145 is about 4492.0090160194. The cubic root of 20178145 is about 272.2453137584.

The spelling of 20178145 in words is "twenty million, one hundred seventy-eight thousand, one hundred forty-five".