91431648 has 432 divisors, whose sum is σ = 358525440. Its totient is φ = 21772800.

The previous prime is 91431643. The next prime is 91431653. The reversal of 91431648 is 84613419.

91431648 is a `hidden beast` number, since 9 + 1 + 4 + 3 + 1 + 648 = 666.

It is an interprime number because it is at equal distance from previous prime (91431643) and next prime (91431653).

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 (91431643) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 2949393 + ... + 2949423.

It is an arithmetic number, because the mean of its divisors is an integer number (829920).

Almost surely, 2^91431648 is an apocalyptic number.

91431648 is a gapful number since it is divisible by the number (98) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 91431648, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (179262720).

91431648 is an abundant number, since it is smaller than the sum of its proper divisors (267093792).

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

91431648 is a wasteful number, since it uses less digits than its factorization.

91431648 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 91 (or 73 counting only the distinct ones).

The product of its digits is 20736, while the sum is 36.

The square root of 91431648 is about 9561.9897510926. The cubic root of 91431648 is about 450.5042052196.

The spelling of 91431648 in words is "ninety-one million, four hundred thirty-one thousand, six hundred forty-eight".