100391218 has 4 divisors (see below), whose sum is σ = 150586830. Its totient is φ = 50195608.

The previous prime is 100391191. The next prime is 100391261. The reversal of 100391218 is 812193001.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 812193001 = 28499².

It can be written as a sum of positive squares in only one way, i.e., 75220929 + 25170289 = 8673^2 + 5017^2 .

It is a junction number, because it is equal to n+sod(n) for n = 100391192 and 100391201.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 25097803 + ... + 25097806.

Almost surely, 2^100391218 is an apocalyptic number.

100391218 is a deficient number, since it is larger than the sum of its proper divisors (50195612).

100391218 is an equidigital number, since it uses as much as digits as its factorization.

100391218 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50195611.

The product of its (nonzero) digits is 432, while the sum is 25.

The square root of 100391218 is about 10019.5418058911. The cubic root of 100391218 is about 464.7633867700.

The spelling of 100391218 in words is "one hundred million, three hundred ninety-one thousand, two hundred eighteen".