20201665 has 16 divisors (see below), whose sum is σ = 26749440. Its totient is φ = 14523520.

The previous prime is 20201663. The next prime is 20201669. The reversal of 20201665 is 56610202.

It is not a de Polignac number, because 20201665 - 2¹ = 20201663 is a prime.

It is a super-3 number, since 3×20201665³ (a number of 23 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (20201663) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2832 + ... + 6958.

It is an arithmetic number, because the mean of its divisors is an integer number (1671840).

Almost surely, 2^20201665 is an apocalyptic number.

It is an amenable number.

20201665 is a deficient number, since it is larger than the sum of its proper divisors (6547775).

20201665 is a wasteful number, since it uses less digits than its factorization.

20201665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4232.

The product of its (nonzero) digits is 720, while the sum is 22.

The square root of 20201665 is about 4494.6262358510. The cubic root of 20201665 is about 272.3510506583.

Adding to 20201665 its reverse (56610202), we get a palindrome (76811867).

The spelling of 20201665 in words is "twenty million, two hundred one thousand, six hundred sixty-five".