20805357 has 4 divisors (see below), whose sum is σ = 27740480. Its totient is φ = 13870236.

The previous prime is 20805353. The next prime is 20805373. The reversal of 20805357 is 75350802.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 20805357 - 2² = 20805353 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20805353) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 3467557 + ... + 3467562.

It is an arithmetic number, because the mean of its divisors is an integer number (6935120).

Almost surely, 2^20805357 is an apocalyptic number.

It is an amenable number.

20805357 is a deficient number, since it is larger than the sum of its proper divisors (6935123).

20805357 is an equidigital number, since it uses as much as digits as its factorization.

20805357 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6935122.

The product of its (nonzero) digits is 8400, while the sum is 30.

The square root of 20805357 is about 4561.2889625631. The cubic root of 20805357 is about 275.0373811444.

The spelling of 20805357 in words is "twenty million, eight hundred five thousand, three hundred fifty-seven".