1991015347 has 2 divisors, whose sum is σ = 1991015348. Its totient is φ = 1991015346.

The previous prime is 1991015321. The next prime is 1991015381. The reversal of 1991015347 is 7435101991.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1991015347 is a prime.

It is a super-2 number, since 2×1991015347² = 7928284223979060818, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1991019347) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 995507673 + 995507674.

It is an arithmetic number, because the mean of its divisors is an integer number (995507674).

Almost surely, 2^1991015347 is an apocalyptic number.

1991015347 is a deficient number, since it is larger than the sum of its proper divisors (1).

1991015347 is an equidigital number, since it uses as much as digits as its factorization.

1991015347 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 34020, while the sum is 40.

The square root of 1991015347 is about 44620.7950063645. The cubic root of 1991015347 is about 1258.0315587534.

The spelling of 1991015347 in words is "one billion, nine hundred ninety-one million, fifteen thousand, three hundred forty-seven".