20438155 has 4 divisors (see below), whose sum is σ = 24525792. Its totient is φ = 16350520.

The previous prime is 20438147. The next prime is 20438161. The reversal of 20438155 is 55183402.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 20438155 - 2³ = 20438147 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2043811 + ... + 2043820.

It is an arithmetic number, because the mean of its divisors is an integer number (6131448).

Almost surely, 2^20438155 is an apocalyptic number.

20438155 is a deficient number, since it is larger than the sum of its proper divisors (4087637).

20438155 is an equidigital number, since it uses as much as digits as its factorization.

20438155 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4087636.

The product of its (nonzero) digits is 4800, while the sum is 28.

The square root of 20438155 is about 4520.8577725914. The cubic root of 20438155 is about 273.4096860198.

The spelling of 20438155 in words is "twenty million, four hundred thirty-eight thousand, one hundred fifty-five".