20616665 has 16 divisors (see below), whose sum is σ = 26645760. Its totient is φ = 15256320.

The previous prime is 20616647. The next prime is 20616667. The reversal of 20616665 is 56661602.

It is not a de Polignac number, because 20616665 - 2⁶ = 20616601 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20616667) 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, 2960 + ... + 7070.

It is an arithmetic number, because the mean of its divisors is an integer number (1665360).

Almost surely, 2^20616665 is an apocalyptic number.

It is an amenable number.

20616665 is a deficient number, since it is larger than the sum of its proper divisors (6029095).

20616665 is a wasteful number, since it uses less digits than its factorization.

20616665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4192.

The product of its (nonzero) digits is 12960, while the sum is 32.

The square root of 20616665 is about 4540.5577851185. The cubic root of 20616665 is about 274.2033805329.

The spelling of 20616665 in words is "twenty million, six hundred sixteen thousand, six hundred sixty-five".