100018391 has 4 divisors (see below), whose sum is σ = 109110984. Its totient is φ = 90925800.

The previous prime is 100018379. The next prime is 100018409. The reversal of 100018391 is 193810001.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 100018391 - 2¹⁸ = 99756247 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (100018351) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4546280 + ... + 4546301.

It is an arithmetic number, because the mean of its divisors is an integer number (27277746).

Almost surely, 2^100018391 is an apocalyptic number.

100018391 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

100018391 is a deficient number, since it is larger than the sum of its proper divisors (9092593).

100018391 is an equidigital number, since it uses as much as digits as its factorization.

100018391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9092592.

The product of its (nonzero) digits is 216, while the sum is 23.

The square root of 100018391 is about 10000.9195077253. The cubic root of 100018391 is about 464.1873361038.

Adding to 100018391 its reverse (193810001), we get a palindrome (293828392).

It can be divided in two parts, 1000 and 18391, that added together give a palindrome (19391).

The spelling of 100018391 in words is "one hundred million, eighteen thousand, three hundred ninety-one".