21002031191 has 2 divisors, whose sum is σ = 21002031192. Its totient is φ = 21002031190.

The previous prime is 21002031151. The next prime is 21002031221. The reversal of 21002031191 is 19113020012.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21002031191 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21002031151) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10501015595 + 10501015596.

It is an arithmetic number, because the mean of its divisors is an integer number (10501015596).

Almost surely, 2^21002031191 is an apocalyptic number.

21002031191 is a deficient number, since it is larger than the sum of its proper divisors (1).

21002031191 is an equidigital number, since it uses as much as digits as its factorization.

21002031191 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 108, while the sum is 20.

The spelling of 21002031191 in words is "twenty-one billion, two million, thirty-one thousand, one hundred ninety-one".