1921388194 has 8 divisors (see below), whose sum is σ = 3144089808. Its totient is φ = 873358260.

The previous prime is 1921388179. The next prime is 1921388197. The reversal of 1921388194 is 4918831291.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (1921388197) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 43667892 + ... + 43667935.

It is an arithmetic number, because the mean of its divisors is an integer number (393011226).

Almost surely, 2^1921388194 is an apocalyptic number.

1921388194 is a deficient number, since it is larger than the sum of its proper divisors (1222701614).

1921388194 is a wasteful number, since it uses less digits than its factorization.

1921388194 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 87335840.

The product of its digits is 124416, while the sum is 46.

The square root of 1921388194 is about 43833.6422625362. The cubic root of 1921388194 is about 1243.1924747686.

The spelling of 1921388194 in words is "one billion, nine hundred twenty-one million, three hundred eighty-eight thousand, one hundred ninety-four".