20920706405 has 4 divisors (see below), whose sum is σ = 25104847692. Its totient is φ = 16736565120.

The previous prime is 20920706369. The next prime is 20920706437. The reversal of 20920706405 is 50460702902.

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 15993649156 + 4927057249 = 126466^2 + 70193^2 .

It is not a de Polignac number, because 20920706405 - 2⁶ = 20920706341 is a prime.

It is a Duffinian number.

It is a plaindrome in base 3 and base 9.

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, 2092070636 + ... + 2092070645.

It is an arithmetic number, because the mean of its divisors is an integer number (6276211923).

Almost surely, 2^20920706405 is an apocalyptic number.

It is an amenable number.

20920706405 is a deficient number, since it is larger than the sum of its proper divisors (4184141287).

20920706405 is an equidigital number, since it uses as much as digits as its factorization.

20920706405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4184141286.

The product of its (nonzero) digits is 30240, while the sum is 35.

The spelling of 20920706405 in words is "twenty billion, nine hundred twenty million, seven hundred six thousand, four hundred five".