1991011892 has 12 divisors (see below), whose sum is σ = 3484692036. Its totient is φ = 995385600.

The previous prime is 1991011871. The next prime is 1991011901. The reversal of 1991011892 is 2981101991.

It can be written as a sum of positive squares in 2 ways, for example, as 1641546256 + 349465636 = 40516^2 + 18694^2 .

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14468 + ... + 64740.

It is an arithmetic number, because the mean of its divisors is an integer number (290391003).

Almost surely, 2^1991011892 is an apocalyptic number.

It is an amenable number.

1991011892 is a deficient number, since it is larger than the sum of its proper divisors (1493680144).

1991011892 is a wasteful number, since it uses less digits than its factorization.

1991011892 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 60178 (or 60176 counting only the distinct ones).

The product of its (nonzero) digits is 11664, while the sum is 41.

The square root of 1991011892 is about 44620.7562912150. The cubic root of 1991011892 is about 1258.0308310675.

Subtracting 1991011892 from its reverse (2981101991), we obtain a palindrome (990090099).

The spelling of 1991011892 in words is "one billion, nine hundred ninety-one million, eleven thousand, eight hundred ninety-two".