20405668513 has 4 divisors (see below), whose sum is σ = 20408692528. Its totient is φ = 20402644500.

The previous prime is 20405668499. The next prime is 20405668519. The reversal of 20405668513 is 31586650402.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20405668513 - 2¹⁷ = 20405537441 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20405668519) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1501863 + ... + 1515388.

It is an arithmetic number, because the mean of its divisors is an integer number (5102173132).

Almost surely, 2^20405668513 is an apocalyptic number.

It is an amenable number.

20405668513 is a deficient number, since it is larger than the sum of its proper divisors (3024015).

20405668513 is an equidigital number, since it uses as much as digits as its factorization.

20405668513 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3024014.

The product of its (nonzero) digits is 172800, while the sum is 40.

The spelling of 20405668513 in words is "twenty billion, four hundred five million, six hundred sixty-eight thousand, five hundred thirteen".