654811721 has 2 divisors, whose sum is σ = 654811722. Its totient is φ = 654811720.

The previous prime is 654811709. The next prime is 654811733. The reversal of 654811721 is 127118456.

It is a balanced prime because it is at equal distance from previous prime (654811709) and next prime (654811733).

It can be written as a sum of positive squares in only one way, i.e., 451350025 + 203461696 = 21245^2 + 14264^2 .

It is a cyclic number.

It is not a de Polignac number, because 654811721 - 2²² = 650617417 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (654811741) 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, 327405860 + 327405861.

It is an arithmetic number, because the mean of its divisors is an integer number (327405861).

Almost surely, 2^654811721 is an apocalyptic number.

It is an amenable number.

654811721 is a deficient number, since it is larger than the sum of its proper divisors (1).

654811721 is an equidigital number, since it uses as much as digits as its factorization.

654811721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 13440, while the sum is 35.

The square root of 654811721 is about 25589.2891851259. The cubic root of 654811721 is about 868.3713402077.

The spelling of 654811721 in words is "six hundred fifty-four million, eight hundred eleven thousand, seven hundred twenty-one".