621864 has 32 divisors (see below), whose sum is σ = 1728000. Its totient is φ = 207216.

The previous prime is 621833. The next prime is 621869. The reversal of 621864 is 468126.

621864 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a nude number because it is divisible by every one of its digits.

It is a plaindrome in base 14.

It is not an unprimeable number, because it can be changed into a prime (621869) by changing a digit.

621864 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1224 + ... + 1655.

It is an arithmetic number, because the mean of its divisors is an integer number (54000).

2⁶²¹⁸⁶⁴ is an apocalyptic number.

It is an amenable number.

621864 is an abundant number, since it is smaller than the sum of its proper divisors (1106136).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

621864 is a wasteful number, since it uses less digits than its factorization.

621864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2894 (or 2884 counting only the distinct ones).

The product of its digits is 2304, while the sum is 27.

The square root of 621864 is about 788.5835402797. The cubic root of 621864 is about 85.3555579048.

621864 divided by its sum of digits (27) gives a palindrome (23032).

It can be divided in two parts, 621 and 864, that added together give a triangular number (1485 = T₅₄).

The spelling of 621864 in words is "six hundred twenty-one thousand, eight hundred sixty-four".