1918928891 has 16 divisors (see below), whose sum is σ = 2152566240. Its totient is φ = 1695271680.

The previous prime is 1918928821. The next prime is 1918928899. The reversal of 1918928891 is 1988298191.

It is a cyclic number.

It is not a de Polignac number, because 1918928891 - 2¹⁴ = 1918912507 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1918928899) 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 15 ways as a sum of consecutive naturals, for example, 403415 + ... + 408143.

It is an arithmetic number, because the mean of its divisors is an integer number (134535390).

Almost surely, 2^1918928891 is an apocalyptic number.

1918928891 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1918928891 is a deficient number, since it is larger than the sum of its proper divisors (233637349).

1918928891 is a wasteful number, since it uses less digits than its factorization.

1918928891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5774.

The product of its digits is 746496, while the sum is 56.

The square root of 1918928891 is about 43805.5805919748. The cubic root of 1918928891 is about 1242.6618354516.

The spelling of 1918928891 in words is "one billion, nine hundred eighteen million, nine hundred twenty-eight thousand, eight hundred ninety-one".