101209891 has 4 divisors (see below), whose sum is σ = 107163432. Its totient is φ = 95256352.

The previous prime is 101209883. The next prime is 101209907. The reversal of 101209891 is 198902101.

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 101209891 - 2³ = 101209883 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (101209811) 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, 2976745 + ... + 2976778.

It is an arithmetic number, because the mean of its divisors is an integer number (26790858).

Almost surely, 2^101209891 is an apocalyptic number.

101209891 is a deficient number, since it is larger than the sum of its proper divisors (5953541).

101209891 is an equidigital number, since it uses as much as digits as its factorization.

101209891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5953540.

The product of its (nonzero) digits is 1296, while the sum is 31.

The square root of 101209891 is about 10060.3126690973. The cubic root of 101209891 is about 466.0233230788.

The spelling of 101209891 in words is "one hundred one million, two hundred nine thousand, eight hundred ninety-one".