20540405 has 8 divisors (see below), whose sum is σ = 24672984. Its totient is φ = 16416000.

The previous prime is 20540393. The next prime is 20540413. The reversal of 20540405 is 50404502.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 550564 + 19989841 = 742^2 + 4471^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20540405 - 2⁶ = 20540341 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 7 ways as a sum of consecutive naturals, for example, 7865 + ... + 10145.

It is an arithmetic number, because the mean of its divisors is an integer number (3084123).

Almost surely, 2^20540405 is an apocalyptic number.

It is an amenable number.

20540405 is a deficient number, since it is larger than the sum of its proper divisors (4132579).

20540405 is a wasteful number, since it uses less digits than its factorization.

20540405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4087.

The product of its (nonzero) digits is 800, while the sum is 20.

The square root of 20540405 is about 4532.1523584275. The cubic root of 20540405 is about 273.8648746767.

Adding to 20540405 its reverse (50404502), we get a palindrome (70944907).

The spelling of 20540405 in words is "twenty million, five hundred forty thousand, four hundred five".