91978488 has 216 divisors, whose sum is σ = 309797280. Its totient is φ = 24554880.

The previous prime is 91978429. The next prime is 91978489. The reversal of 91978488 is 88487919.

91978488 is a `hidden beast` number, since 91 + 9 + 78 + 488 = 666.

It is a super-2 number, since 2×91978488² = 16920084509532288, which contains 22 as substring.

It is a nude number because it is divisible by every one of its digits.

Its product of digits (1161216) is a multiple of the sum of its prime divisors (72).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91978489) by changing a digit.

It is a polite number, since it can be written in 53 ways as a sum of consecutive naturals, for example, 2967033 + ... + 2967063.

Almost surely, 2^91978488 is an apocalyptic number.

91978488 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 91978488, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (154898640).

91978488 is an abundant number, since it is smaller than the sum of its proper divisors (217818792).

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

91978488 is a wasteful number, since it uses less digits than its factorization.

91978488 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 115 (or 72 counting only the distinct ones).

The product of its digits is 1161216, while the sum is 54.

The square root of 91978488 is about 9590.5415905464. The cubic root of 91978488 is about 451.4005549868.

The spelling of 91978488 in words is "ninety-one million, nine hundred seventy-eight thousand, four hundred eighty-eight".