621216 has 48 divisors (see below), whose sum is σ = 1814400. Its totient is φ = 206784.

The previous prime is 621143. The next prime is 621217. The reversal of 621216 is 612126.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (48).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a nude number because it is divisible by every one of its digits and also a Zuckerman number because it is divisible by the product of its digits.

It is a plaindrome in base 13 and base 14.

It is not an unprimeable number, because it can be changed into a prime (621217) by changing a digit.

621216 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, 505 + ... + 1223.

It is an arithmetic number, because the mean of its divisors is an integer number (37800).

2⁶²¹²¹⁶ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 621216, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (907200).

621216 is an abundant number, since it is smaller than the sum of its proper divisors (1193184).

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

621216 is a wasteful number, since it uses less digits than its factorization.

621216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 738 (or 724 counting only the distinct ones).

The product of its digits is 144, while the sum is 18.

The square root of 621216 is about 788.1725699363. The cubic root of 621216 is about 85.3258999601.

The spelling of 621216 in words is "six hundred twenty-one thousand, two hundred sixteen".