20169865 has 8 divisors (see below), whose sum is σ = 24228360. Its totient is φ = 16119552.

The previous prime is 20169859. The next prime is 20169883. The reversal of 20169865 is 56896102.

It can be written as a sum of positive squares in 4 ways, for example, as 7382089 + 12787776 = 2717^2 + 3576^2 .

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 20169865 - 2⁹ = 20169353 is a prime.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 7137 + ... + 9553.

It is an arithmetic number, because the mean of its divisors is an integer number (3028545).

Almost surely, 2^20169865 is an apocalyptic number.

It is an amenable number.

20169865 is a deficient number, since it is larger than the sum of its proper divisors (4058495).

20169865 is a wasteful number, since it uses less digits than its factorization.

20169865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4091.

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

The square root of 20169865 is about 4491.0872848343. The cubic root of 20169865 is about 272.2080705001.

It can be divided in two parts, 2016 and 9865, that added together give a square (11881 = 109²).

The spelling of 20169865 in words is "twenty million, one hundred sixty-nine thousand, eight hundred sixty-five".