921509680 has 240 divisors, whose sum is σ = 2725138080. Its totient is φ = 288916992.

The previous prime is 921509669. The next prime is 921509681. The reversal of 921509680 is 86905129.

It is a Harshad number since it is a multiple of its sum of digits (40).

It is not an unprimeable number, because it can be changed into a prime (921509681) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 8612187 + ... + 8612293.

It is an arithmetic number, because the mean of its divisors is an integer number (11354742).

Almost surely, 2^921509680 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 921509680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1362569040).

921509680 is an abundant number, since it is smaller than the sum of its proper divisors (1803628400).

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

921509680 is a wasteful number, since it uses less digits than its factorization.

921509680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 173 (or 134 counting only the distinct ones).

The product of its (nonzero) digits is 38880, while the sum is 40.

The square root of 921509680 is about 30356.3779130515. The cubic root of 921509680 is about 973.1205274844.

The spelling of 921509680 in words is "nine hundred twenty-one million, five hundred nine thousand, six hundred eighty".