1991136670 has 16 divisors (see below), whose sum is σ = 3660303168. Its totient is φ = 779508640.

The previous prime is 1991136659. The next prime is 1991136671. The reversal of 1991136670 is 766311991.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1991136671) 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, 2117761 + ... + 2118700.

It is an arithmetic number, because the mean of its divisors is an integer number (228768948).

Almost surely, 2^1991136670 is an apocalyptic number.

1991136670 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1991136670 is a deficient number, since it is larger than the sum of its proper divisors (1669166498).

1991136670 is a wasteful number, since it uses less digits than its factorization.

1991136670 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4236515.

The product of its (nonzero) digits is 61236, while the sum is 43.

The square root of 1991136670 is about 44622.1544751035. The cubic root of 1991136670 is about 1258.0571110532.

The spelling of 1991136670 in words is "one billion, nine hundred ninety-one million, one hundred thirty-six thousand, six hundred seventy".