100991789 has 4 divisors (see below), whose sum is σ = 101025120. Its totient is φ = 100958460.

The previous prime is 100991743. The next prime is 100991801. The reversal of 100991789 is 987199001.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-100991789 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 (100991719) 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, 11609 + ... + 18350.

It is an arithmetic number, because the mean of its divisors is an integer number (25256280).

Almost surely, 2^100991789 is an apocalyptic number.

It is an amenable number.

100991789 is a deficient number, since it is larger than the sum of its proper divisors (33331).

100991789 is an equidigital number, since it uses as much as digits as its factorization.

100991789 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33330.

The product of its (nonzero) digits is 40824, while the sum is 44.

The square root of 100991789 is about 10049.4671002994. The cubic root of 100991789 is about 465.6883304037.

The spelling of 100991789 in words is "one hundred million, nine hundred ninety-one thousand, seven hundred eighty-nine".