1991954195 has 16 divisors (see below), whose sum is σ = 2980171008. Its totient is φ = 1241737440.

The previous prime is 1991954171. The next prime is 1991954227. The reversal of 1991954195 is 5914591991.

It is not a de Polignac number, because 1991954195 - 2⁶ = 1991954131 is a prime.

It is a Duffinian number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 2586569 + ... + 2587338.

It is an arithmetic number, because the mean of its divisors is an integer number (186260688).

Almost surely, 2^1991954195 is an apocalyptic number.

1991954195 is a deficient number, since it is larger than the sum of its proper divisors (988216813).

1991954195 is a wasteful number, since it uses less digits than its factorization.

1991954195 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5173930.

The product of its digits is 656100, while the sum is 53.

The square root of 1991954195 is about 44631.3140631104. The cubic root of 1991954195 is about 1258.2292660551.

The spelling of 1991954195 in words is "one billion, nine hundred ninety-one million, nine hundred fifty-four thousand, one hundred ninety-five".