891332640 has 192 divisors, whose sum is σ = 3403451520. Its totient is φ = 216069120.

The previous prime is 891332621. The next prime is 891332653. The reversal of 891332640 is 46233198.

891332640 is a `hidden beast` number, since 8 + 9 + 1 + 3 + 3 + 2 + 640 = 666.

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 = 891332595 and 891332604.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 38142 + ... + 56898.

It is an arithmetic number, because the mean of its divisors is an integer number (17726310).

Almost surely, 2^891332640 is an apocalyptic number.

891332640 is a gapful number since it is divisible by the number (80) 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 891332640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1701725760).

891332640 is an abundant number, since it is smaller than the sum of its proper divisors (2512118880).

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

891332640 is a wasteful number, since it uses less digits than its factorization.

891332640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18792 (or 18778 counting only the distinct ones).

The product of its (nonzero) digits is 31104, while the sum is 36.

The square root of 891332640 is about 29855.1945228967. The cubic root of 891332640 is about 962.3800320482.

The spelling of 891332640 in words is "eight hundred ninety-one million, three hundred thirty-two thousand, six hundred forty".