891728640 has 432 divisors, whose sum is σ = 3489647616. Its totient is φ = 208281600.

The previous prime is 891728611. The next prime is 891728687. The reversal of 891728640 is 46827198.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 3928207 + ... + 3928433.

It is an arithmetic number, because the mean of its divisors is an integer number (8077888).

Almost surely, 2^891728640 is an apocalyptic number.

891728640 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 891728640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1744823808).

891728640 is an abundant number, since it is smaller than the sum of its proper divisors (2597918976).

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

891728640 is a wasteful number, since it uses less digits than its factorization.

891728640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 296 (or 279 counting only the distinct ones).

The product of its (nonzero) digits is 193536, while the sum is 45.

The square root of 891728640 is about 29861.8257981658. The cubic root of 891728640 is about 962.5225325585.

The spelling of 891728640 in words is "eight hundred ninety-one million, seven hundred twenty-eight thousand, six hundred forty".