2154905 has 4 divisors (see below), whose sum is σ = 2585892. Its totient is φ = 1723920.

The previous prime is 2154899. The next prime is 2154907. The reversal of 2154905 is 5094512.

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

It can be written as a sum of positive squares in 2 ways, for example, as 524176 + 1630729 = 724^2 + 1277^2 .

It is not a de Polignac number, because 2154905 - 2¹² = 2150809 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2154907) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 215486 + ... + 215495.

It is an arithmetic number, because the mean of its divisors is an integer number (646473).

2^2154905 is an apocalyptic number.

It is an amenable number.

2154905 is a deficient number, since it is larger than the sum of its proper divisors (430987).

2154905 is an equidigital number, since it uses as much as digits as its factorization.

2154905 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 430986.

The product of its (nonzero) digits is 1800, while the sum is 26.

The square root of 2154905 is about 1467.9594681053. The cubic root of 2154905 is about 129.1643639317.

The spelling of 2154905 in words is "two million, one hundred fifty-four thousand, nine hundred five".