8400905 has 4 divisors (see below), whose sum is σ = 10081092. Its totient is φ = 6720720.

The previous prime is 8400901. The next prime is 8400919. The reversal of 8400905 is 5090048.

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 4206601 + 4194304 = 2051^2 + 2048^2 .

It is not a de Polignac number, because 8400905 - 2² = 8400901 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (8400901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 840086 + ... + 840095.

It is an arithmetic number, because the mean of its divisors is an integer number (2520273).

Almost surely, 2^8400905 is an apocalyptic number.

It is an amenable number.

8400905 is a deficient number, since it is larger than the sum of its proper divisors (1680187).

8400905 is a wasteful number, since it uses less digits than its factorization.

8400905 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1680186.

The product of its (nonzero) digits is 1440, while the sum is 26.

The square root of 8400905 is about 2898.4314723657. The cubic root of 8400905 is about 203.2865714080.

The spelling of 8400905 in words is "eight million, four hundred thousand, nine hundred five".