891630720 has 128 divisors (see below), whose sum is σ = 3157920000. Its totient is φ = 237763584.

The previous prime is 891630697. The next prime is 891630721. The reversal of 891630720 is 27036198.

It is a tau number, because it is divible by the number of its divisors (128).

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

It is not an unprimeable number, because it can be changed into a prime (891630721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8520 + ... + 43079.

It is an arithmetic number, because the mean of its divisors is an integer number (24671250).

Almost surely, 2^891630720 is an apocalyptic number.

891630720 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 891630720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1578960000).

891630720 is an abundant number, since it is smaller than the sum of its proper divisors (2266289280).

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

891630720 is a wasteful number, since it uses less digits than its factorization.

891630720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51627 (or 51609 counting only the distinct ones).

The product of its (nonzero) digits is 18144, while the sum is 36.

The square root of 891630720 is about 29860.1862016967. The cubic root of 891630720 is about 962.4872999955.

The spelling of 891630720 in words is "eight hundred ninety-one million, six hundred thirty thousand, seven hundred twenty".