621728 has 12 divisors (see below), whose sum is σ = 1224090. Its totient is φ = 310848.

The previous prime is 621721. The next prime is 621739. The reversal of 621728 is 827126.

It can be written as a sum of positive squares in only one way, i.e., 620944 + 784 = 788^2 + 28^2 .

It is a junction number, because it is equal to n+sod(n) for n = 621697 and 621706.

It is not an unprimeable number, because it can be changed into a prime (621721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9683 + ... + 9746.

2⁶²¹⁷²⁸ is an apocalyptic number.

It is an amenable number.

621728 is a deficient number, since it is larger than the sum of its proper divisors (602362).

621728 is a wasteful number, since it uses less digits than its factorization.

621728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19439 (or 19431 counting only the distinct ones).

The product of its digits is 1344, while the sum is 26.

The square root of 621728 is about 788.4973050049. The cubic root of 621728 is about 85.3493351068.

The spelling of 621728 in words is "six hundred twenty-one thousand, seven hundred twenty-eight".