100143991 has 12 divisors (see below), whose sum is σ = 107049672. Its totient is φ = 93661568.

The previous prime is 100143983. The next prime is 100143997. The reversal of 100143991 is 199341001.

It is a happy number.

It is not a de Polignac number, because 100143991 - 2³ = 100143983 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 (100143997) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 48996 + ... + 50998.

It is an arithmetic number, because the mean of its divisors is an integer number (8920806).

Almost surely, 2^100143991 is an apocalyptic number.

100143991 is a deficient number, since it is larger than the sum of its proper divisors (6905681).

100143991 is a wasteful number, since it uses less digits than its factorization.

100143991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2210 (or 2193 counting only the distinct ones).

The product of its (nonzero) digits is 972, while the sum is 28.

The square root of 100143991 is about 10007.1969601882. The cubic root of 100143991 is about 464.3815588571.

Adding to 100143991 its reverse (199341001), we get a palindrome (299484992).

The spelling of 100143991 in words is "one hundred million, one hundred forty-three thousand, nine hundred ninety-one".