626821 has 6 divisors (see below), whose sum is σ = 678930. Its totient is φ = 578448.

The previous prime is 626809. The next prime is 626833. The reversal of 626821 is 128626.

It is an interprime number because it is at equal distance from previous prime (626809) and next prime (626833).

It can be written as a sum of positive squares in 3 ways, for example, as 9025 + 617796 = 95^2 + 786^2 .

It is not a de Polignac number, because 626821 - 2⁷ = 626693 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (626861) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1686 + ... + 2023.

It is an arithmetic number, because the mean of its divisors is an integer number (113155).

2⁶²⁶⁸²¹ is an apocalyptic number.

It is an amenable number.

626821 is a deficient number, since it is larger than the sum of its proper divisors (52109).

626821 is a wasteful number, since it uses less digits than its factorization.

626821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3735 (or 3722 counting only the distinct ones).

The product of its digits is 1152, while the sum is 25.

The square root of 626821 is about 791.7202788864. The cubic root of 626821 is about 85.5817532511.

The spelling of 626821 in words is "six hundred twenty-six thousand, eight hundred twenty-one".