921664 has 14 divisors (see below), whose sum is σ = 1829054. Its totient is φ = 460800.

The previous prime is 921647. The next prime is 921667. The reversal of 921664 is 466129.

It can be written as a sum of positive squares in only one way, i.e., 921600 + 64 = 960^2 + 8^2 .

It is not an unprimeable number, because it can be changed into a prime (921667) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7137 + ... + 7264.

2⁹²¹⁶⁶⁴ is an apocalyptic number.

It is an amenable number.

921664 is a deficient number, since it is larger than the sum of its proper divisors (907390).

921664 is a wasteful number, since it uses less digits than its factorization.

921664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14413 (or 14403 counting only the distinct ones).

The product of its digits is 2592, while the sum is 28.

The square root of 921664 is about 960.0333327546. The cubic root of 921664 is about 97.3174845444.

Subtracting from 921664 its reverse (466129), we obtain a triangular number (455535 = T₉₅₄).

It can be divided in two parts, 9216 and 64, that multiplied together give a square (589824 = 768²).

The spelling of 921664 in words is "nine hundred twenty-one thousand, six hundred sixty-four".