649032581 has 2 divisors, whose sum is σ = 649032582. Its totient is φ = 649032580.

The previous prime is 649032569. The next prime is 649032623. The reversal of 649032581 is 185230946.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 560032225 + 89000356 = 23665^2 + 9434^2 .

It is a cyclic number.

It is not a de Polignac number, because 649032581 - 2¹⁴ = 649016197 is a prime.

It is a super-2 number, since 2×649032581² = 842486582399043122, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (649035581) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 324516290 + 324516291.

It is an arithmetic number, because the mean of its divisors is an integer number (324516291).

Almost surely, 2^649032581 is an apocalyptic number.

It is an amenable number.

649032581 is a deficient number, since it is larger than the sum of its proper divisors (1).

649032581 is an equidigital number, since it uses as much as digits as its factorization.

649032581 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 51840, while the sum is 38.

The square root of 649032581 is about 25476.1178557487. The cubic root of 649032581 is about 865.8091400777.

The spelling of 649032581 in words is "six hundred forty-nine million, thirty-two thousand, five hundred eighty-one".