621811 has 4 divisors (see below), whose sum is σ = 627952. Its totient is φ = 615672.

The previous prime is 621799. The next prime is 621821. The reversal of 621811 is 118126.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 118126 = 2 ⋅59063.

It is a cyclic number.

It is not a de Polignac number, because 621811 - 2⁵ = 621779 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (621821) 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 3 ways as a sum of consecutive naturals, for example, 2916 + ... + 3121.

It is an arithmetic number, because the mean of its divisors is an integer number (156988).

2⁶²¹⁸¹¹ is an apocalyptic number.

621811 is a deficient number, since it is larger than the sum of its proper divisors (6141).

621811 is a wasteful number, since it uses less digits than its factorization.

621811 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6140.

The product of its digits is 96, while the sum is 19.

The square root of 621811 is about 788.5499350073. The cubic root of 621811 is about 85.3531329517.

Adding to 621811 its reverse (118126), we get a palindrome (739937).

The spelling of 621811 in words is "six hundred twenty-one thousand, eight hundred eleven".