1020109991 has 2 divisors, whose sum is σ = 1020109992. Its totient is φ = 1020109990.

The previous prime is 1020109967. The next prime is 1020110033. The reversal of 1020109991 is 1999010201.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1020109991 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1020109891) 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, 510054995 + 510054996.

It is an arithmetic number, because the mean of its divisors is an integer number (510054996).

Almost surely, 2^1020109991 is an apocalyptic number.

1020109991 is a deficient number, since it is larger than the sum of its proper divisors (1).

1020109991 is an equidigital number, since it uses as much as digits as its factorization.

1020109991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1458, while the sum is 32.

The square root of 1020109991 is about 31939.1607748231. The cubic root of 1020109991 is about 1006.6588910826.

The spelling of 1020109991 in words is "one billion, twenty million, one hundred nine thousand, nine hundred ninety-one".