20405229 has 24 divisors (see below), whose sum is σ = 29760192. Its totient is φ = 12430080.

The previous prime is 20405213. The next prime is 20405233. The reversal of 20405229 is 92250402.

20405229 = 57² + 58² + ... + 394².

It is not a de Polignac number, because 20405229 - 2⁴ = 20405213 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 20405199 and 20405208.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20405239) 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 23 ways as a sum of consecutive naturals, for example, 84549 + ... + 84789.

It is an arithmetic number, because the mean of its divisors is an integer number (1240008).

Almost surely, 2^20405229 is an apocalyptic number.

It is an amenable number.

20405229 is a deficient number, since it is larger than the sum of its proper divisors (9354963).

20405229 is a wasteful number, since it uses less digits than its factorization.

20405229 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 437 (or 424 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 24.

The square root of 20405229 is about 4517.2147391949. The cubic root of 20405229 is about 273.2627855144.

The spelling of 20405229 in words is "twenty million, four hundred five thousand, two hundred twenty-nine".