20005405 has 8 divisors (see below), whose sum is σ = 27436032. Its totient is φ = 13717968.

The previous prime is 20005397. The next prime is 20005429. The reversal of 20005405 is 50450002.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 20005405 - 2³ = 20005397 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, 285757 + ... + 285826.

It is an arithmetic number, because the mean of its divisors is an integer number (3429504).

Almost surely, 2^20005405 is an apocalyptic number.

It is an amenable number.

20005405 is a deficient number, since it is larger than the sum of its proper divisors (7430627).

20005405 is an equidigital number, since it uses as much as digits as its factorization.

20005405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 571595.

The product of its (nonzero) digits is 200, while the sum is 16.

The square root of 20005405 is about 4472.7402115482. The cubic root of 20005405 is about 271.4662118358.

Adding to 20005405 its reverse (50450002), we get a palindrome (70455407).

The spelling of 20005405 in words is "twenty million, five thousand, four hundred five".