101009991 has 4 divisors (see below), whose sum is σ = 134679992. Its totient is φ = 67339992.

The previous prime is 101009983. The next prime is 101010031. The reversal of 101009991 is 199900101.

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

It is not a de Polignac number, because 101009991 - 2³ = 101009983 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 (101009911) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16834996 + ... + 16835001.

It is an arithmetic number, because the mean of its divisors is an integer number (33669998).

Almost surely, 2^101009991 is an apocalyptic number.

101009991 is a deficient number, since it is larger than the sum of its proper divisors (33670001).

101009991 is an equidigital number, since it uses as much as digits as its factorization.

101009991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33670000.

The product of its (nonzero) digits is 729, while the sum is 30.

The square root of 101009991 is about 10050.3726796572. The cubic root of 101009991 is about 465.7163061097.

The spelling of 101009991 in words is "one hundred one million, nine thousand, nine hundred ninety-one".