91531839672 has 240 divisors, whose sum is σ = 321173150760. Its totient is φ = 24140156544.

The previous prime is 91531839649. The next prime is 91531839677. The reversal of 91531839672 is 27693813519.

91531839672 is a `hidden beast` number, since 9 + 1 + 531 + 8 + 39 + 6 + 72 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91531839677) by changing a digit.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 301903 + ... + 523649.

Almost surely, 2^91531839672 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 91531839672, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (160586575380).

91531839672 is an abundant number, since it is smaller than the sum of its proper divisors (229641311088).

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

91531839672 is a wasteful number, since it uses less digits than its factorization.

91531839672 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 221792 (or 221772 counting only the distinct ones).

The product of its digits is 2449440, while the sum is 54.

The spelling of 91531839672 in words is "ninety-one billion, five hundred thirty-one million, eight hundred thirty-nine thousand, six hundred seventy-two".