621643 has 8 divisors (see below), whose sum is σ = 700416. Its totient is φ = 546600.

The previous prime is 621641. The next prime is 621671. The reversal of 621643 is 346126.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 621643 - 2¹ = 621641 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (621641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 571 + ... + 1252.

It is an arithmetic number, because the mean of its divisors is an integer number (87552).

2⁶²¹⁶⁴³ is an apocalyptic number.

621643 is a deficient number, since it is larger than the sum of its proper divisors (78773).

621643 is a wasteful number, since it uses less digits than its factorization.

621643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1865.

The product of its digits is 864, while the sum is 22.

The square root of 621643 is about 788.4434031685. The cubic root of 621643 is about 85.3454453972.

Adding to 621643 its reverse (346126), we get a palindrome (967769).

The spelling of 621643 in words is "six hundred twenty-one thousand, six hundred forty-three".