1991804029 has 4 divisors (see below), whose sum is σ = 2096635840. Its totient is φ = 1886972220.

The previous prime is 1991803999. The next prime is 1991804057. The reversal of 1991804029 is 9204081991.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1991804029 - 2¹⁵ = 1991771261 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1991804429) by changing a digit.

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, 52415877 + ... + 52415914.

It is an arithmetic number, because the mean of its divisors is an integer number (524158960).

Almost surely, 2^1991804029 is an apocalyptic number.

1991804029 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

It is an amenable number.

1991804029 is a deficient number, since it is larger than the sum of its proper divisors (104831811).

1991804029 is a wasteful number, since it uses less digits than its factorization.

1991804029 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 104831810.

The product of its (nonzero) digits is 46656, while the sum is 43.

The square root of 1991804029 is about 44629.6317372214. The cubic root of 1991804029 is about 1258.1976475228.

The spelling of 1991804029 in words is "one billion, nine hundred ninety-one million, eight hundred four thousand, twenty-nine".