4001405 has 4 divisors (see below), whose sum is σ = 4801692. Its totient is φ = 3201120.

The previous prime is 4001399. The next prime is 4001407. The reversal of 4001405 is 5041004.

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 2896804 + 1104601 = 1702^2 + 1051^2 .

It is a de Polignac number, because none of the positive numbers 2^k-4001405 is a prime.

It is a super-2 number, since 2×4001405² = 32022483948050, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 4001405.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (4001407) 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, 400136 + ... + 400145.

It is an arithmetic number, because the mean of its divisors is an integer number (1200423).

Almost surely, 2^4001405 is an apocalyptic number.

It is an amenable number.

4001405 is a deficient number, since it is larger than the sum of its proper divisors (800287).

4001405 is an equidigital number, since it uses as much as digits as its factorization.

4001405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 800286.

The product of its (nonzero) digits is 80, while the sum is 14.

The square root of 4001405 is about 2000.3512191613. The cubic root of 4001405 is about 158.7586888418.

Adding to 4001405 its reverse (5041004), we get a palindrome (9042409).

The spelling of 4001405 in words is "four million, one thousand, four hundred five".