19871191031 has 2 divisors, whose sum is σ = 19871191032. Its totient is φ = 19871191030.

The previous prime is 19871191019. The next prime is 19871191037. The reversal of 19871191031 is 13019117891.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19871191031 is a prime.

It is a super-2 number, since 2×19871191031² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 19871191031.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19871191037) 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, 9935595515 + 9935595516.

It is an arithmetic number, because the mean of its divisors is an integer number (9935595516).

Almost surely, 2^19871191031 is an apocalyptic number.

19871191031 is a deficient number, since it is larger than the sum of its proper divisors (1).

19871191031 is an equidigital number, since it uses as much as digits as its factorization.

19871191031 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 13608, while the sum is 41.

The spelling of 19871191031 in words is "nineteen billion, eight hundred seventy-one million, one hundred ninety-one thousand, thirty-one".