20401405 has 4 divisors (see below), whose sum is σ = 24481692. Its totient is φ = 16321120.

The previous prime is 20401397. The next prime is 20401427. The reversal of 20401405 is 50410402.

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 5331481 + 15069924 = 2309^2 + 3882^2 .

It is not a de Polignac number, because 20401405 - 2³ = 20401397 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, 2040136 + ... + 2040145.

It is an arithmetic number, because the mean of its divisors is an integer number (6120423).

Almost surely, 2^20401405 is an apocalyptic number.

It is an amenable number.

20401405 is a deficient number, since it is larger than the sum of its proper divisors (4080287).

20401405 is an equidigital number, since it uses as much as digits as its factorization.

20401405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4080286.

The product of its (nonzero) digits is 160, while the sum is 16.

The square root of 20401405 is about 4516.7914496908. The cubic root of 20401405 is about 273.2457143644.

Adding to 20401405 its reverse (50410402), we get a palindrome (70811807).

The spelling of 20401405 in words is "twenty million, four hundred one thousand, four hundred five".