1991015345 has 8 divisors (see below), whose sum is σ = 2606420160. Its totient is φ = 1448011120.

The previous prime is 1991015321. The next prime is 1991015347. The reversal of 1991015345 is 5435101991.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1991015345 - 2¹⁰ = 1991014321 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1991015299 and 1991015308.

It is not an unprimeable number, because it can be changed into a prime (1991015347) 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 in 7 ways as a sum of consecutive naturals, for example, 18100085 + ... + 18100194.

It is an arithmetic number, because the mean of its divisors is an integer number (325802520).

Almost surely, 2^1991015345 is an apocalyptic number.

It is an amenable number.

1991015345 is a deficient number, since it is larger than the sum of its proper divisors (615404815).

1991015345 is a wasteful number, since it uses less digits than its factorization.

1991015345 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36200295.

The product of its (nonzero) digits is 24300, while the sum is 38.

The square root of 1991015345 is about 44620.7949839534. The cubic root of 1991015345 is about 1258.0315583322.

The spelling of 1991015345 in words is "one billion, nine hundred ninety-one million, fifteen thousand, three hundred forty-five".