20855511851 has 2 divisors, whose sum is σ = 20855511852. Its totient is φ = 20855511850.

The previous prime is 20855511827. The next prime is 20855511863. The reversal of 20855511851 is 15811555802.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20855511851 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20855511799 and 20855511808.

It is not a weakly prime, because it can be changed into another prime (20855511811) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10427755925 + 10427755926.

It is an arithmetic number, because the mean of its divisors is an integer number (10427755926).

Almost surely, 2^20855511851 is an apocalyptic number.

20855511851 is a deficient number, since it is larger than the sum of its proper divisors (1).

20855511851 is an equidigital number, since it uses as much as digits as its factorization.

20855511851 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 80000, while the sum is 41.

The spelling of 20855511851 in words is "twenty billion, eight hundred fifty-five million, five hundred eleven thousand, eight hundred fifty-one".