621918 has 40 divisors (see below), whose sum is σ = 1524600. Its totient is φ = 187920.

The previous prime is 621913. The next prime is 621923. The reversal of 621918 is 819126.

It is an interprime number because it is at equal distance from previous prime (621913) and next prime (621923).

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

It is a junction number, because it is equal to n+sod(n) for n = 621891 and 621900.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (621913) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 1608 + ... + 1956.

It is an arithmetic number, because the mean of its divisors is an integer number (38115).

2⁶²¹⁹¹⁸ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 621918, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (762300).

621918 is an abundant number, since it is smaller than the sum of its proper divisors (902682).

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

621918 is a wasteful number, since it uses less digits than its factorization.

621918 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 374 (or 365 counting only the distinct ones).

The product of its digits is 864, while the sum is 27.

The square root of 621918 is about 788.6177781410. The cubic root of 621918 is about 85.3580284700.

The spelling of 621918 in words is "six hundred twenty-one thousand, nine hundred eighteen".