91231515648 has 1232 divisors, whose sum is σ = 360843194880. Its totient is φ = 22359048192.

The previous prime is 91231515647. The next prime is 91231515659. The reversal of 91231515648 is 84651513219.

It is a happy number.

91231515648 is a `hidden beast` number, since 9 + 1 + 2 + 31 + 51 + 564 + 8 = 666.

It is a super-3 number, since 3×91231515648³ (a number of 34 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91231515647) by changing a digit.

It is a polite number, since it can be written in 111 ways as a sum of consecutive naturals, for example, 1154829273 + ... + 1154829351.

Almost surely, 2^91231515648 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 91231515648, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (180421597440).

91231515648 is an abundant number, since it is smaller than the sum of its proper divisors (269611679232).

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

91231515648 is a wasteful number, since it uses less digits than its factorization.

91231515648 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 154 (or 121 counting only the distinct ones).

The product of its digits is 259200, while the sum is 45.

The spelling of 91231515648 in words is "ninety-one billion, two hundred thirty-one million, five hundred fifteen thousand, six hundred forty-eight".