20813205 has 16 divisors (see below), whose sum is σ = 38058624. Its totient is φ = 9514560.

The previous prime is 20813201. The next prime is 20813207. The reversal of 20813205 is 50231802.

It is not a de Polignac number, because 20813205 - 2² = 20813201 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20813201) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 99006 + ... + 99215.

It is an arithmetic number, because the mean of its divisors is an integer number (2378664).

Almost surely, 2^20813205 is an apocalyptic number.

It is an amenable number.

20813205 is a deficient number, since it is larger than the sum of its proper divisors (17245419).

20813205 is a wasteful number, since it uses less digits than its factorization.

20813205 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 198236.

The product of its (nonzero) digits is 480, while the sum is 21.

The square root of 20813205 is about 4562.1491645934. The cubic root of 20813205 is about 275.0719591303.

The spelling of 20813205 in words is "twenty million, eight hundred thirteen thousand, two hundred five".