1918251993 has 16 divisors (see below), whose sum is σ = 2930426240. Its totient is φ = 1093378176.

The previous prime is 1918251991. The next prime is 1918251997. The reversal of 1918251993 is 3991528191.

It is not a de Polignac number, because 1918251993 - 2¹ = 1918251991 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1918251991) 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, 106708 + ... + 123381.

It is an arithmetic number, because the mean of its divisors is an integer number (183151640).

Almost surely, 2^1918251993 is an apocalyptic number.

It is an amenable number.

1918251993 is a deficient number, since it is larger than the sum of its proper divisors (1012174247).

1918251993 is a wasteful number, since it uses less digits than its factorization.

1918251993 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 230496.

The product of its digits is 174960, while the sum is 48.

The square root of 1918251993 is about 43797.8537487855. The cubic root of 1918251993 is about 1242.5157028461.

The spelling of 1918251993 in words is "one billion, nine hundred eighteen million, two hundred fifty-one thousand, nine hundred ninety-three".