20111131987 has 2 divisors, whose sum is σ = 20111131988. Its totient is φ = 20111131986.

The previous prime is 20111131981. The next prime is 20111131991. The reversal of 20111131987 is 78913111102.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20111131987 - 2³ = 20111131979 is a prime.

It is not a weakly prime, because it can be changed into another prime (20111131981) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10055565993 + 10055565994.

It is an arithmetic number, because the mean of its divisors is an integer number (10055565994).

Almost surely, 2^20111131987 is an apocalyptic number.

20111131987 is a deficient number, since it is larger than the sum of its proper divisors (1).

20111131987 is an equidigital number, since it uses as much as digits as its factorization.

20111131987 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3024, while the sum is 34.

The spelling of 20111131987 in words is "twenty billion, one hundred eleven million, one hundred thirty-one thousand, nine hundred eighty-seven".