20855112569 has 2 divisors, whose sum is σ = 20855112570. Its totient is φ = 20855112568.

The previous prime is 20855112541. The next prime is 20855112587. The reversal of 20855112569 is 96521155802.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11209515625 + 9645596944 = 105875^2 + 98212^2 .

It is a cyclic number.

It is not a de Polignac number, because 20855112569 - 2¹² = 20855108473 is a prime.

It is a super-2 number, since 2×20855112569² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (20855112539) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10427556284 + 10427556285.

It is an arithmetic number, because the mean of its divisors is an integer number (10427556285).

Almost surely, 2^20855112569 is an apocalyptic number.

It is an amenable number.

20855112569 is a deficient number, since it is larger than the sum of its proper divisors (1).

20855112569 is an equidigital number, since it uses as much as digits as its factorization.

20855112569 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 216000, while the sum is 44.

The spelling of 20855112569 in words is "twenty billion, eight hundred fifty-five million, one hundred twelve thousand, five hundred sixty-nine".