921388 has 36 divisors (see below), whose sum is σ = 1844640. Its totient is φ = 401856.

The previous prime is 921379. The next prime is 921407. The reversal of 921388 is 883129.

921388 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an unprimeable number.

921388 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 19581 + ... + 19627.

It is an arithmetic number, because the mean of its divisors is an integer number (51240).

2⁹²¹³⁸⁸ is an apocalyptic number.

It is an amenable number.

921388 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

921388 is a wasteful number, since it uses less digits than its factorization.

921388 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 106 (or 91 counting only the distinct ones).

The product of its digits is 3456, while the sum is 31.

The square root of 921388 is about 959.8895769827. The cubic root of 921388 is about 97.3077693961.

The spelling of 921388 in words is "nine hundred twenty-one thousand, three hundred eighty-eight".