921688 has 8 divisors (see below), whose sum is σ = 1728180. Its totient is φ = 460840.

The previous prime is 921677. The next prime is 921703. The reversal of 921688 is 886129.

It is a tau number, because it is divible by the number of its divisors (8).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 57598 + ... + 57613.

2⁹²¹⁶⁸⁸ is an apocalyptic number.

It is an amenable number.

921688 is a deficient number, since it is larger than the sum of its proper divisors (806492).

921688 is a wasteful number, since it uses less digits than its factorization.

921688 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 115217 (or 115213 counting only the distinct ones).

The product of its digits is 6912, while the sum is 34.

The square root of 921688 is about 960.0458322393. The cubic root of 921688 is about 97.3183292483.

The spelling of 921688 in words is "nine hundred twenty-one thousand, six hundred eighty-eight".