91618380 has 288 divisors, whose sum is σ = 345945600. Its totient is φ = 19160064.

The previous prime is 91618379. The next prime is 91618391. The reversal of 91618380 is 8381619.

91618380 is a `hidden beast` number, since 9 + 1 + 618 + 38 + 0 = 666.

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

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 1029376 + ... + 1029464.

It is an arithmetic number, because the mean of its divisors is an integer number (1201200).

Almost surely, 2^91618380 is an apocalyptic number.

91618380 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 91618380, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (172972800).

91618380 is an abundant number, since it is smaller than the sum of its proper divisors (254327220).

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

91618380 is a wasteful number, since it uses less digits than its factorization.

91618380 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 173 (or 168 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 36.

The square root of 91618380 is about 9571.7490564682. The cubic root of 91618380 is about 450.8106867976.

Adding to 91618380 its sum of digits (36), we get a triangular number (91618416 = T₁₃₅₃₆).

Adding to 91618380 its reverse (8381619), we get a palindrome (99999999).

The spelling of 91618380 in words is "ninety-one million, six hundred eighteen thousand, three hundred eighty".