20871965399 has 2 divisors, whose sum is σ = 20871965400. Its totient is φ = 20871965398.

The previous prime is 20871965381. The next prime is 20871965447. The reversal of 20871965399 is 99356917802.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20871965399 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20871965999) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10435982699 + 10435982700.

It is an arithmetic number, because the mean of its divisors is an integer number (10435982700).

Almost surely, 2^20871965399 is an apocalyptic number.

20871965399 is a deficient number, since it is larger than the sum of its proper divisors (1).

20871965399 is an equidigital number, since it uses as much as digits as its factorization.

20871965399 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7348320, while the sum is 59.

The spelling of 20871965399 in words is "twenty billion, eight hundred seventy-one million, nine hundred sixty-five thousand, three hundred ninety-nine".