20730665 has 4 divisors (see below), whose sum is σ = 24876804. Its totient is φ = 16584528.

The previous prime is 20730623. The next prime is 20730719. The reversal of 20730665 is 56603702.

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 9467929 + 11262736 = 3077^2 + 3356^2 .

It is a cyclic number.

It is not a de Polignac number, because 20730665 - 2¹⁸ = 20468521 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, 2073062 + ... + 2073071.

It is an arithmetic number, because the mean of its divisors is an integer number (6219201).

Almost surely, 2^20730665 is an apocalyptic number.

It is an amenable number.

20730665 is a deficient number, since it is larger than the sum of its proper divisors (4146139).

20730665 is an equidigital number, since it uses as much as digits as its factorization.

20730665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4146138.

The product of its (nonzero) digits is 7560, while the sum is 29.

The square root of 20730665 is about 4553.0940029830. The cubic root of 20730665 is about 274.7078550403.

The spelling of 20730665 in words is "twenty million, seven hundred thirty thousand, six hundred sixty-five".