20545813 has 4 divisors (see below), whose sum is σ = 20599020. Its totient is φ = 20492608.

The previous prime is 20545807. The next prime is 20545817. The reversal of 20545813 is 31854502.

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 1387684 + 19158129 = 1178^2 + 4377^2 .

It is a cyclic number.

It is not a de Polignac number, because 20545813 - 2⁵ = 20545781 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 (20545817) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26020 + ... + 26797.

It is an arithmetic number, because the mean of its divisors is an integer number (5149755).

Almost surely, 2^20545813 is an apocalyptic number.

It is an amenable number.

20545813 is a deficient number, since it is larger than the sum of its proper divisors (53207).

20545813 is an equidigital number, since it uses as much as digits as its factorization.

20545813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53206.

The product of its (nonzero) digits is 4800, while the sum is 28.

The square root of 20545813 is about 4532.7489451766. The cubic root of 20545813 is about 273.8889074921. Note that the first 3 decimals are identical.

The spelling of 20545813 in words is "twenty million, five hundred forty-five thousand, eight hundred thirteen".