20016665 has 4 divisors (see below), whose sum is σ = 24020004. Its totient is φ = 16013328.

The previous prime is 20016649. The next prime is 20016677. The reversal of 20016665 is 56661002.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 10163344 + 9853321 = 3188^2 + 3139^2 .

It is a cyclic number.

It is not a de Polignac number, because 20016665 - 2⁴ = 20016649 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2001662 + ... + 2001671.

It is an arithmetic number, because the mean of its divisors is an integer number (6005001).

Almost surely, 2^20016665 is an apocalyptic number.

It is an amenable number.

20016665 is a deficient number, since it is larger than the sum of its proper divisors (4003339).

20016665 is an equidigital number, since it uses as much as digits as its factorization.

20016665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4003338.

The product of its (nonzero) digits is 2160, while the sum is 26.

The square root of 20016665 is about 4473.9987706748. The cubic root of 20016665 is about 271.5171336781.

Adding to 20016665 its reverse (56661002), we get a palindrome (76677667).

The spelling of 20016665 in words is "twenty million, sixteen thousand, six hundred sixty-five".