91136440 has 64 divisors (see below), whose sum is σ = 213736320. Its totient is φ = 34944000.

The previous prime is 91136413. The next prime is 91136467. The reversal of 91136440 is 4463119.

It is an interprime number because it is at equal distance from previous prime (91136413) and next prime (91136467).

It is a junction number, because it is equal to n+sod(n) for n = 91136399 and 91136408.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 99585 + ... + 100495.

It is an arithmetic number, because the mean of its divisors is an integer number (3339630).

Almost surely, 2^91136440 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 91136440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (106868160).

91136440 is an abundant number, since it is smaller than the sum of its proper divisors (122599880).

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

91136440 is a wasteful number, since it uses less digits than its factorization.

With its predecessor (91136439) it forms a Ruth-Aaron pair, since the sum of their prime factors is the same (1024).

91136440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1024 (or 1020 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 28.

The square root of 91136440 is about 9546.5407347374. The cubic root of 91136440 is about 450.0188304877.

Adding to 91136440 its reverse (4463119), we get a palindrome (95599559).

The spelling of 91136440 in words is "ninety-one million, one hundred thirty-six thousand, four hundred forty".