100721191 has 2 divisors, whose sum is σ = 100721192. Its totient is φ = 100721190.

The previous prime is 100721183. The next prime is 100721213. The reversal of 100721191 is 191127001.

It is an a-pointer prime, because the next prime (100721213) can be obtained adding 100721191 to its sum of digits (22).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 100721191 - 2³ = 100721183 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (100721591) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 50360595 + 50360596.

It is an arithmetic number, because the mean of its divisors is an integer number (50360596).

Almost surely, 2^100721191 is an apocalyptic number.

100721191 is a deficient number, since it is larger than the sum of its proper divisors (1).

100721191 is an equidigital number, since it uses as much as digits as its factorization.

100721191 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 126, while the sum is 22.

The square root of 100721191 is about 10035.9947688308. The cubic root of 100721191 is about 465.2720356806.

Adding to 100721191 its reverse (191127001), we get a palindrome (291848192).

The spelling of 100721191 in words is "one hundred million, seven hundred twenty-one thousand, one hundred ninety-one".