921621408 has 192 divisors, whose sum is σ = 2739889152. Its totient is φ = 269660160.

The previous prime is 921621383. The next prime is 921621439. The reversal of 921621408 is 804126129.

It is an unprimeable number.

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 31 ways as a sum of consecutive naturals, for example, 1613763 + ... + 1614333.

It is an arithmetic number, because the mean of its divisors is an integer number (14270256).

Almost surely, 2^921621408 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 921621408, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1369944576).

921621408 is an abundant number, since it is smaller than the sum of its proper divisors (1818267744).

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

921621408 is a wasteful number, since it uses less digits than its factorization.

921621408 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 667 (or 659 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 33.

The square root of 921621408 is about 30358.2181295280. The cubic root of 921621408 is about 973.1598544059.

The spelling of 921621408 in words is "nine hundred twenty-one million, six hundred twenty-one thousand, four hundred eight".