91218101 has 4 divisors (see below), whose sum is σ = 98234892. Its totient is φ = 84201312.

The previous prime is 91218059. The next prime is 91218109. The reversal of 91218101 is 10181219.

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

It can be written as a sum of positive squares in 2 ways, for example, as 42915601 + 48302500 = 6551^2 + 6950^2 .

It is not a de Polignac number, because 91218101 - 2⁶ = 91218037 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91218109) 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, 3508376 + ... + 3508401.

It is an arithmetic number, because the mean of its divisors is an integer number (24558723).

Almost surely, 2^91218101 is an apocalyptic number.

It is an amenable number.

91218101 is a deficient number, since it is larger than the sum of its proper divisors (7016791).

91218101 is a wasteful number, since it uses less digits than its factorization.

91218101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7016790.

The product of its (nonzero) digits is 144, while the sum is 23.

The square root of 91218101 is about 9550.8167713552. The cubic root of 91218101 is about 450.1532005125.

It can be divided in two parts, 91218 and 101, that added together give a palindrome (91319).

The spelling of 91218101 in words is "ninety-one million, two hundred eighteen thousand, one hundred one".