20171745 has 24 divisors (see below), whose sum is σ = 38143872. Its totient is φ = 9780000.

The previous prime is 20171729. The next prime is 20171777. The reversal of 20171745 is 54717102.

It is not a de Polignac number, because 20171745 - 2⁴ = 20171729 is a prime.

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 19881 + ... + 20870.

It is an arithmetic number, because the mean of its divisors is an integer number (1589328).

Almost surely, 2^20171745 is an apocalyptic number.

It is an amenable number.

20171745 is a deficient number, since it is larger than the sum of its proper divisors (17972127).

20171745 is a wasteful number, since it uses less digits than its factorization.

20171745 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40773 (or 40770 counting only the distinct ones).

The product of its (nonzero) digits is 1960, while the sum is 27.

The square root of 20171745 is about 4491.2965833933. The cubic root of 20171745 is about 272.2165275931.

Adding to 20171745 its reverse (54717102), we get a palindrome (74888847).

The spelling of 20171745 in words is "twenty million, one hundred seventy-one thousand, seven hundred forty-five".