20775845 has 4 divisors (see below), whose sum is σ = 24931020. Its totient is φ = 16620672.

The previous prime is 20775809. The next prime is 20775851. The reversal of 20775845 is 54857702.

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 3751969 + 17023876 = 1937^2 + 4126^2 .

It is a cyclic number.

It is not a de Polignac number, because 20775845 - 2⁸ = 20775589 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 20775799 and 20775808.

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, 2077580 + ... + 2077589.

It is an arithmetic number, because the mean of its divisors is an integer number (6232755).

Almost surely, 2^20775845 is an apocalyptic number.

It is an amenable number.

20775845 is a deficient number, since it is larger than the sum of its proper divisors (4155175).

20775845 is an equidigital number, since it uses as much as digits as its factorization.

20775845 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4155174.

The product of its (nonzero) digits is 78400, while the sum is 38.

The square root of 20775845 is about 4558.0527640649. The cubic root of 20775845 is about 274.9072745231.

The spelling of 20775845 in words is "twenty million, seven hundred seventy-five thousand, eight hundred forty-five".