621871 has 2 divisors, whose sum is σ = 621872. Its totient is φ = 621870.

The previous prime is 621869. The next prime is 621883. The reversal of 621871 is 178126.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 621871 - 2¹ = 621869 is a prime.

Together with 621869, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another 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 as a sum of consecutive naturals, namely, 310935 + 310936.

It is an arithmetic number, because the mean of its divisors is an integer number (310936).

2⁶²¹⁸⁷¹ is an apocalyptic number.

621871 is a deficient number, since it is larger than the sum of its proper divisors (1).

621871 is an equidigital number, since it uses as much as digits as its factorization.

621871 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 672, while the sum is 25.

The square root of 621871 is about 788.5879786048. The cubic root of 621871 is about 85.3558781713.

Adding to 621871 its reverse (178126), we get a palindrome (799997).

The spelling of 621871 in words is "six hundred twenty-one thousand, eight hundred seventy-one".