20690805 has 8 divisors (see below), whose sum is σ = 33105312. Its totient is φ = 11035088.

The previous prime is 20690797. The next prime is 20690827. The reversal of 20690805 is 50809602.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20690805 - 2³ = 20690797 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 689679 + ... + 689708.

It is an arithmetic number, because the mean of its divisors is an integer number (4138164).

Almost surely, 2^20690805 is an apocalyptic number.

It is an amenable number.

20690805 is a deficient number, since it is larger than the sum of its proper divisors (12414507).

20690805 is a wasteful number, since it uses less digits than its factorization.

20690805 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1379395.

The product of its (nonzero) digits is 4320, while the sum is 30.

The square root of 20690805 is about 4548.7146536137. The cubic root of 20690805 is about 274.5316767304.

The spelling of 20690805 in words is "twenty million, six hundred ninety thousand, eight hundred five".