20506016851 has 6 divisors (see below), whose sum is σ = 20816649420. Its totient is φ = 20199952476.

The previous prime is 20506016837. The next prime is 20506016863. The reversal of 20506016851 is 15861060502.

It is a happy number.

It is not a de Polignac number, because 20506016851 - 2²⁵ = 20472462419 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20506016051) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2279541 + ... + 2288518.

It is an arithmetic number, because the mean of its divisors is an integer number (3469441570).

Almost surely, 2^20506016851 is an apocalyptic number.

20506016851 is a deficient number, since it is larger than the sum of its proper divisors (310632569).

20506016851 is an frugal number, since it uses more digits than its factorization.

20506016851 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4568193 (or 4568126 counting only the distinct ones).

The product of its (nonzero) digits is 14400, while the sum is 34.

The spelling of 20506016851 in words is "twenty billion, five hundred six million, sixteen thousand, eight hundred fifty-one".