20857715111 has 2 divisors, whose sum is σ = 20857715112. Its totient is φ = 20857715110.

The previous prime is 20857715107. The next prime is 20857715141. The reversal of 20857715111 is 11151775802.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20857715111 - 2² = 20857715107 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20857715141) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10428857555 + 10428857556.

It is an arithmetic number, because the mean of its divisors is an integer number (10428857556).

Almost surely, 2^20857715111 is an apocalyptic number.

20857715111 is a deficient number, since it is larger than the sum of its proper divisors (1).

20857715111 is an equidigital number, since it uses as much as digits as its factorization.

20857715111 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 19600, while the sum is 38.

The spelling of 20857715111 in words is "twenty billion, eight hundred fifty-seven million, seven hundred fifteen thousand, one hundred eleven".