20918229 has 4 divisors (see below), whose sum is σ = 27890976. Its totient is φ = 13945484.

The previous prime is 20918203. The next prime is 20918237. The reversal of 20918229 is 92281902.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20918229 - 2⁵ = 20918197 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20918229.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20918239) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3486369 + ... + 3486374.

It is an arithmetic number, because the mean of its divisors is an integer number (6972744).

Almost surely, 2^20918229 is an apocalyptic number.

It is an amenable number.

20918229 is a deficient number, since it is larger than the sum of its proper divisors (6972747).

20918229 is an equidigital number, since it uses as much as digits as its factorization.

20918229 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6972746.

The product of its (nonzero) digits is 5184, while the sum is 33.

The square root of 20918229 is about 4573.6450452566. The cubic root of 20918229 is about 275.5338566191.

The spelling of 20918229 in words is "twenty million, nine hundred eighteen thousand, two hundred twenty-nine".