20217813 has 16 divisors (see below), whose sum is σ = 33609216. Its totient is φ = 10502640.

The previous prime is 20217793. The next prime is 20217817. The reversal of 20217813 is 31871202.

It is not a de Polignac number, because 20217813 - 2⁶ = 20217749 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20217817) 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, 43531 + ... + 43992.

It is an arithmetic number, because the mean of its divisors is an integer number (2100576).

Almost surely, 2^20217813 is an apocalyptic number.

It is an amenable number.

20217813 is a deficient number, since it is larger than the sum of its proper divisors (13391403).

20217813 is a wasteful number, since it uses less digits than its factorization.

20217813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 87544.

The product of its (nonzero) digits is 672, while the sum is 24.

The square root of 20217813 is about 4496.4222444072. The cubic root of 20217813 is about 272.4235983661.

The spelling of 20217813 in words is "twenty million, two hundred seventeen thousand, eight hundred thirteen".