20612005405 has 4 divisors (see below), whose sum is σ = 24734406492. Its totient is φ = 16489604320.

The previous prime is 20612005387. The next prime is 20612005411. The reversal of 20612005405 is 50450021602.

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 15428869369 + 5183136036 = 124213^2 + 71994^2 .

It is not a de Polignac number, because 20612005405 - 2¹⁷ = 20611874333 is a prime.

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 20612005405.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2061200536 + ... + 2061200545.

It is an arithmetic number, because the mean of its divisors is an integer number (6183601623).

Almost surely, 2^20612005405 is an apocalyptic number.

It is an amenable number.

20612005405 is a deficient number, since it is larger than the sum of its proper divisors (4122401087).

20612005405 is an equidigital number, since it uses as much as digits as its factorization.

20612005405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4122401086.

The product of its (nonzero) digits is 2400, while the sum is 25.

The spelling of 20612005405 in words is "twenty billion, six hundred twelve million, five thousand, four hundred five".