654921809 has 2 divisors, whose sum is σ = 654921810. Its totient is φ = 654921808.

The previous prime is 654921797. The next prime is 654921857. The reversal of 654921809 is 908129456.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 572166400 + 82755409 = 23920^2 + 9097^2 .

It is a cyclic number.

It is not a de Polignac number, because 654921809 - 2¹⁶ = 654856273 is a prime.

It is a super-3 number, since 3×654921809³ (a number of 27 digits) contains 333 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 654921809.

It is not a weakly prime, because it can be changed into another prime (654921899) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 327460904 + 327460905.

It is an arithmetic number, because the mean of its divisors is an integer number (327460905).

Almost surely, 2^654921809 is an apocalyptic number.

It is an amenable number.

654921809 is a deficient number, since it is larger than the sum of its proper divisors (1).

654921809 is an equidigital number, since it uses as much as digits as its factorization.

654921809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 155520, while the sum is 44.

The square root of 654921809 is about 25591.4401509567. The cubic root of 654921809 is about 868.4200014764.

The spelling of 654921809 in words is "six hundred fifty-four million, nine hundred twenty-one thousand, eight hundred nine".