20697785 has 4 divisors (see below), whose sum is σ = 24837348. Its totient is φ = 16558224.

The previous prime is 20697779. The next prime is 20697797. The reversal of 20697785 is 58779602.

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 16152361 + 4545424 = 4019^2 + 2132^2 .

It is a cyclic number.

It is not a de Polignac number, because 20697785 - 2¹⁰ = 20696761 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, 2069774 + ... + 2069783.

It is an arithmetic number, because the mean of its divisors is an integer number (6209337).

Almost surely, 2^20697785 is an apocalyptic number.

It is an amenable number.

20697785 is a deficient number, since it is larger than the sum of its proper divisors (4139563).

20697785 is an equidigital number, since it uses as much as digits as its factorization.

20697785 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4139562.

The product of its (nonzero) digits is 211680, while the sum is 44.

The square root of 20697785 is about 4549.4818386273. The cubic root of 20697785 is about 274.5625441562.

The spelling of 20697785 in words is "twenty million, six hundred ninety-seven thousand, seven hundred eighty-five".