91218621312 has 256 divisors, whose sum is σ = 331350835200. Its totient is φ = 24057575424.

The previous prime is 91218621289. The next prime is 91218621313. The reversal of 91218621312 is 21312681219.

91218621312 is a `hidden beast` number, since 9 + 1 + 2 + 18 + 621 + 3 + 12 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91218621313) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 169473 + ... + 459519.

It is an arithmetic number, because the mean of its divisors is an integer number (1294339200).

Almost surely, 2^91218621312 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 91218621312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (165675417600).

91218621312 is an abundant number, since it is smaller than the sum of its proper divisors (240132213888).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

91218621312 is a wasteful number, since it uses less digits than its factorization.

91218621312 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 290090 (or 290072 counting only the distinct ones).

The product of its digits is 10368, while the sum is 36.

The spelling of 91218621312 in words is "ninety-one billion, two hundred eighteen million, six hundred twenty-one thousand, three hundred twelve".