20438405 has 16 divisors (see below), whose sum is σ = 26717040. Its totient is φ = 14919168.

The previous prime is 20438389. The next prime is 20438413. The reversal of 20438405 is 50483402.

It can be written as a sum of positive squares in 8 ways, for example, as 1350244 + 19088161 = 1162^2 + 4369^2 .

It is a cyclic number.

It is not a de Polignac number, because 20438405 - 2⁴ = 20438389 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4019 + ... + 7551.

It is an arithmetic number, because the mean of its divisors is an integer number (1669815).

Almost surely, 2^20438405 is an apocalyptic number.

It is an amenable number.

20438405 is a deficient number, since it is larger than the sum of its proper divisors (6278635).

20438405 is a wasteful number, since it uses less digits than its factorization.

20438405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3640.

The product of its (nonzero) digits is 3840, while the sum is 26.

The square root of 20438405 is about 4520.8854221270. The cubic root of 20438405 is about 273.4108007999.

The spelling of 20438405 in words is "twenty million, four hundred thirty-eight thousand, four hundred five".