20506139697 has 4 divisors (see below), whose sum is σ = 27341519600. Its totient is φ = 13670759796.

The previous prime is 20506139669. The next prime is 20506139701. The reversal of 20506139697 is 79693160502.

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 not a de Polignac number, because 20506139697 - 2¹⁰ = 20506138673 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20506139497) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3417689947 + ... + 3417689952.

It is an arithmetic number, because the mean of its divisors is an integer number (6835379900).

Almost surely, 2^20506139697 is an apocalyptic number.

It is an amenable number.

20506139697 is a deficient number, since it is larger than the sum of its proper divisors (6835379903).

20506139697 is an equidigital number, since it uses as much as digits as its factorization.

20506139697 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6835379902.

The product of its (nonzero) digits is 612360, while the sum is 48.

The spelling of 20506139697 in words is "twenty billion, five hundred six million, one hundred thirty-nine thousand, six hundred ninety-seven".