621816 has 32 divisors (see below), whose sum is σ = 1674960. Its totient is φ = 191232.

The previous prime is 621799. The next prime is 621821. The reversal of 621816 is 618126.

It is a Harshad number since it is a multiple of its sum of digits (24).

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

It is a congruent number.

It is an unprimeable number.

621816 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, 685 + ... + 1308.

2⁶²¹⁸¹⁶ is an apocalyptic number.

It is an amenable number.

621816 is an abundant number, since it is smaller than the sum of its proper divisors (1053144).

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

621816 is a wasteful number, since it uses less digits than its factorization.

621816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2015 (or 2011 counting only the distinct ones).

The product of its digits is 576, while the sum is 24.

The square root of 621816 is about 788.5531053772. The cubic root of 621816 is about 85.3533617268.

The spelling of 621816 in words is "six hundred twenty-one thousand, eight hundred sixteen".