20509950847 has 2 divisors, whose sum is σ = 20509950848. Its totient is φ = 20509950846.

The previous prime is 20509950841. The next prime is 20509950947. The reversal of 20509950847 is 74805990502.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20509950847 - 2¹⁹ = 20509426559 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20509950847.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20509950841) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10254975423 + 10254975424.

It is an arithmetic number, because the mean of its divisors is an integer number (10254975424).

Almost surely, 2^20509950847 is an apocalyptic number.

20509950847 is a deficient number, since it is larger than the sum of its proper divisors (1).

20509950847 is an equidigital number, since it uses as much as digits as its factorization.

20509950847 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 907200, while the sum is 49.

The spelling of 20509950847 in words is "twenty billion, five hundred nine million, nine hundred fifty thousand, eight hundred forty-seven".