40405 has 4 divisors (see below), whose sum is σ = 48492. Its totient is φ = 32320.

The previous prime is 40387. The next prime is 40423. The reversal of 40405 is 50404.

40405 = 59² + 60² + ... + 68².

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

It is an interprime number because it is at equal distance from previous prime (40387) and next prime (40423).

It can be written as a sum of positive squares in 2 ways, for example, as 14161 + 26244 = 119^2 + 162^2 .

It is not a de Polignac number, because 40405 - 2⁷ = 40277 is a prime.

It is a Duffinian number.

40405 is a lucky 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, 4036 + ... + 4045.

It is an arithmetic number, because the mean of its divisors is an integer number (12123).

2⁴⁰⁴⁰⁵ is an apocalyptic number.

It is an amenable number.

40405 is a deficient number, since it is larger than the sum of its proper divisors (8087).

40405 is an equidigital number, since it uses as much as digits as its factorization.

40405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8086.

The product of its (nonzero) digits is 80, while the sum is 13.

The square root of 40405 is about 201.0099500025. The cubic root of 40405 is about 34.3145549326.

Adding to 40405 its reverse (50404), we get a palindrome (90809).

Subtracting 40405 from its reverse (50404), we obtain a palindrome (9999).

The spelling of 40405 in words is "forty thousand, four hundred five".