91077840 has 240 divisors, whose sum is σ = 370476288. Its totient is φ = 19574784.

The previous prime is 91077839. The next prime is 91077841. The reversal of 91077840 is 4877019.

It is an interprime number because it is at equal distance from previous prime (91077839) and next prime (91077841).

It is a tau number, because it is divible by the number of its divisors (240).

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

It is a junction number, because it is equal to n+sod(n) for n = 91077795 and 91077804.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91077841) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 85149 + ... + 86211.

Almost surely, 2^91077840 is an apocalyptic number.

91077840 is a gapful number since it is divisible by the number (90) 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 91077840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (185238144).

91077840 is an abundant number, since it is smaller than the sum of its proper divisors (279398448).

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

91077840 is a wasteful number, since it uses less digits than its factorization.

91077840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1106 (or 1097 counting only the distinct ones).

The product of its (nonzero) digits is 14112, while the sum is 36.

The square root of 91077840 is about 9543.4710666507. The cubic root of 91077840 is about 449.9223569746.

The spelling of 91077840 in words is "ninety-one million, seventy-seven thousand, eight hundred forty".