100400191 has 4 divisors (see below), whose sum is σ = 100627272. Its totient is φ = 100173112.

The previous prime is 100400189. The next prime is 100400197. The reversal of 100400191 is 191004001.

It is a happy number.

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 100400191 - 2¹ = 100400189 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 (100400197) 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, 112876 + ... + 113761.

It is an arithmetic number, because the mean of its divisors is an integer number (25156818).

Almost surely, 2^100400191 is an apocalyptic number.

100400191 is a deficient number, since it is larger than the sum of its proper divisors (227081).

100400191 is an equidigital number, since it uses as much as digits as its factorization.

100400191 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 227080.

The product of its (nonzero) digits is 36, while the sum is 16.

The square root of 100400191 is about 10019.9895708529. The cubic root of 100400191 is about 464.7772332588. Note that the first 3 decimals are identical.

Adding to 100400191 its reverse (191004001), we get a palindrome (291404192).

The spelling of 100400191 in words is "one hundred million, four hundred thousand, one hundred ninety-one".