20509019837 has 2 divisors, whose sum is σ = 20509019838. Its totient is φ = 20509019836.

The previous prime is 20509019831. The next prime is 20509019857. The reversal of 20509019837 is 73891090502.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10911682681 + 9597337156 = 104459^2 + 97966^2 .

It is a cyclic number.

It is not a de Polignac number, because 20509019837 - 2⁸ = 20509019581 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20509019831) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10254509918 + 10254509919.

It is an arithmetic number, because the mean of its divisors is an integer number (10254509919).

Almost surely, 2^20509019837 is an apocalyptic number.

It is an amenable number.

20509019837 is a deficient number, since it is larger than the sum of its proper divisors (1).

20509019837 is an equidigital number, since it uses as much as digits as its factorization.

20509019837 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 136080, while the sum is 44.

The spelling of 20509019837 in words is "twenty billion, five hundred nine million, nineteen thousand, eight hundred thirty-seven".