1991846385 has 12 divisors (see below), whose sum is σ = 3452533812. Its totient is φ = 1062318048.

The previous prime is 1991846383. The next prime is 1991846447. The reversal of 1991846385 is 5836481991.

1991846385 is a `hidden beast` number, since 1 + 99 + 18 + 463 + 85 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 1301838561 + 690007824 = 36081^2 + 26268^2 .

It is not a de Polignac number, because 1991846385 - 2¹ = 1991846383 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1991846383) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 22131582 + ... + 22131671.

It is an arithmetic number, because the mean of its divisors is an integer number (287711151).

Almost surely, 2^1991846385 is an apocalyptic number.

1991846385 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1991846385 is a deficient number, since it is larger than the sum of its proper divisors (1460687427).

1991846385 is a wasteful number, since it uses less digits than its factorization.

1991846385 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44263264 (or 44263261 counting only the distinct ones).

The product of its digits is 1866240, while the sum is 54.

The square root of 1991846385 is about 44630.1062624771. The cubic root of 1991846385 is about 1258.2065660444.

The spelling of 1991846385 in words is "one billion, nine hundred ninety-one million, eight hundred forty-six thousand, three hundred eighty-five".