193991988 has 12 divisors (see below), whose sum is σ = 452648000. Its totient is φ = 64663992.

The previous prime is 193991977. The next prime is 193991989. The reversal of 193991988 is 889199391.

It is a tau number, because it is divible by the number of its divisors (12).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (193991989) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8082988 + ... + 8083011.

Almost surely, 2^193991988 is an apocalyptic number.

It is an amenable number.

193991988 is an abundant number, since it is smaller than the sum of its proper divisors (258656012).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

193991988 is a wasteful number, since it uses less digits than its factorization.

193991988 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16166006 (or 16166004 counting only the distinct ones).

The product of its digits is 1259712, while the sum is 57.

The square root of 193991988 is about 13928.1006601762. The cubic root of 193991988 is about 578.8880678267. Note that the first 3 decimals are identical.

The spelling of 193991988 in words is "one hundred ninety-three million, nine hundred ninety-one thousand, nine hundred eighty-eight".