20549813 has 2 divisors, whose sum is σ = 20549814. Its totient is φ = 20549812.

The previous prime is 20549801. The next prime is 20549827. The reversal of 20549813 is 31894502.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14799409 + 5750404 = 3847^2 + 2398^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20549813 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20549813.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20549843) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10274906 + 10274907.

It is an arithmetic number, because the mean of its divisors is an integer number (10274907).

Almost surely, 2^20549813 is an apocalyptic number.

It is an amenable number.

20549813 is a deficient number, since it is larger than the sum of its proper divisors (1).

20549813 is an equidigital number, since it uses as much as digits as its factorization.

20549813 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8640, while the sum is 32.

The square root of 20549813 is about 4533.1901570528. The cubic root of 20549813 is about 273.9066805300.

The spelling of 20549813 in words is "twenty million, five hundred forty-nine thousand, eight hundred thirteen".