1921628018 has 18 divisors (see below), whose sum is σ = 2916405999. Its totient is φ = 949624092.

The previous prime is 1921628017. The next prime is 1921628021. The reversal of 1921628018 is 8108261291.

It can be written as a sum of positive squares in only one way, i.e., 960814009 + 960814009 = 30997^2 + 30997^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=30997.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1921628017) 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 8 ways as a sum of consecutive naturals, for example, 8617055 + ... + 8617277.

Almost surely, 2^1921628018 is an apocalyptic number.

1921628018 is a deficient number, since it is larger than the sum of its proper divisors (994777981).

1921628018 is an frugal number, since it uses more digits than its factorization.

1921628018 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 726 (or 364 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 38.

The square root of 1921628018 is about 43836.3777928788. The cubic root of 1921628018 is about 1243.2441969191.

The spelling of 1921628018 in words is "one billion, nine hundred twenty-one million, six hundred twenty-eight thousand, eighteen".