654821 has 2 divisors, whose sum is σ = 654822. Its totient is φ = 654820.

The previous prime is 654817. The next prime is 654827. The reversal of 654821 is 128456.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 390625 + 264196 = 625^2 + 514^2 .

It is a cyclic number.

It is not a de Polignac number, because 654821 - 2² = 654817 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (654827) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 327410 + 327411.

It is an arithmetic number, because the mean of its divisors is an integer number (327411).

2⁶⁵⁴⁸²¹ is an apocalyptic number.

It is an amenable number.

654821 is a deficient number, since it is larger than the sum of its proper divisors (1).

654821 is an equidigital number, since it uses as much as digits as its factorization.

654821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1920, while the sum is 26.

The square root of 654821 is about 809.2101086862. The cubic root of 654821 is about 86.8375441936.

The spelling of 654821 in words is "six hundred fifty-four thousand, eight hundred twenty-one".