20643085 has 4 divisors (see below), whose sum is σ = 24771708. Its totient is φ = 16514464.

The previous prime is 20643061. The next prime is 20643107. The reversal of 20643085 is 58034602.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 58034602 = 2 ⋅29017301.

It can be written as a sum of positive squares in 2 ways, for example, as 14969161 + 5673924 = 3869^2 + 2382^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20643085 is a prime.

It is a super-2 number, since 2×20643085² = 852273916634450, which contains 22 as substring.

It is a Duffinian number.

It is a congruent 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, 2064304 + ... + 2064313.

It is an arithmetic number, because the mean of its divisors is an integer number (6192927).

Almost surely, 2^20643085 is an apocalyptic number.

It is an amenable number.

20643085 is a deficient number, since it is larger than the sum of its proper divisors (4128623).

20643085 is an equidigital number, since it uses as much as digits as its factorization.

20643085 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4128622.

The product of its (nonzero) digits is 5760, while the sum is 28.

The square root of 20643085 is about 4543.4661878350. The cubic root of 20643085 is about 274.3204599435.

Adding to 20643085 its reverse (58034602), we get a palindrome (78677687).

The spelling of 20643085 in words is "twenty million, six hundred forty-three thousand, eighty-five".