921628 has 12 divisors (see below), whose sum is σ = 1627920. Its totient is φ = 456512.

The previous prime is 921611. The next prime is 921629. The reversal of 921628 is 826129.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 921596 and 921605.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (921629) by changing a digit.

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 in 3 ways as a sum of consecutive naturals, for example, 568 + ... + 1471.

It is an arithmetic number, because the mean of its divisors is an integer number (135660).

2⁹²¹⁶²⁸ is an apocalyptic number.

It is an amenable number.

921628 is a deficient number, since it is larger than the sum of its proper divisors (706292).

921628 is a wasteful number, since it uses less digits than its factorization.

921628 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2156 (or 2154 counting only the distinct ones).

The product of its digits is 1728, while the sum is 28.

The square root of 921628 is about 960.0145832226. The cubic root of 921628 is about 97.3162174612.

Subtracting from 921628 its sum of digits (28), we obtain a square (921600 = 960²).

The spelling of 921628 in words is "nine hundred twenty-one thousand, six hundred twenty-eight".