8240405 has 4 divisors (see below), whose sum is σ = 9888492. Its totient is φ = 6592320.

The previous prime is 8240399. The next prime is 8240431. The reversal of 8240405 is 5040428.

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 4268356 + 3972049 = 2066^2 + 1993^2 .

It is not a de Polignac number, because 8240405 - 2⁶ = 8240341 is a prime.

It is a Duffinian number.

It is a congruent 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, 824036 + ... + 824045.

It is an arithmetic number, because the mean of its divisors is an integer number (2472123).

Almost surely, 2^8240405 is an apocalyptic number.

It is an amenable number.

8240405 is a deficient number, since it is larger than the sum of its proper divisors (1648087).

8240405 is a wasteful number, since it uses less digits than its factorization.

8240405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1648086.

The product of its (nonzero) digits is 1280, while the sum is 23.

The square root of 8240405 is about 2870.6105622324. The cubic root of 8240405 is about 201.9836358995.

Adding to 8240405 its sum of digits (23), we get a palindrome (8240428).

The spelling of 8240405 in words is "eight million, two hundred forty thousand, four hundred five".