1993811091 has 4 divisors (see below), whose sum is σ = 2658414792. Its totient is φ = 1329207392.

The previous prime is 1993811089. The next prime is 1993811101. The reversal of 1993811091 is 1901183991.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1993811091 - 2¹ = 1993811089 is a prime.

It is a super-2 number, since 2×1993811091² = 7950565333189220562, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1993811191) 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, 332301846 + ... + 332301851.

It is an arithmetic number, because the mean of its divisors is an integer number (664603698).

Almost surely, 2^1993811091 is an apocalyptic number.

1993811091 is a deficient number, since it is larger than the sum of its proper divisors (664603701).

1993811091 is an equidigital number, since it uses as much as digits as its factorization.

1993811091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 664603700.

The product of its (nonzero) digits is 17496, while the sum is 42.

The square root of 1993811091 is about 44652.1118313569. Note that the first 3 decimals coincide. The cubic root of 1993811091 is about 1258.6201176246.

The spelling of 1993811091 in words is "one billion, nine hundred ninety-three million, eight hundred eleven thousand, ninety-one".