649964781 has 6 divisors (see below), whose sum is σ = 938838030. Its totient is φ = 433309848.

The previous prime is 649964779. The next prime is 649964801. The reversal of 649964781 is 187469946.

It can be written as a sum of positive squares in only one way, i.e., 638370756 + 11594025 = 25266^2 + 3405^2 .

It is not a de Polignac number, because 649964781 - 2¹ = 649964779 is a prime.

It is a super-2 number, since 2×649964781² = 844908433080755922, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (649964701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 36109146 + ... + 36109163.

It is an arithmetic number, because the mean of its divisors is an integer number (156473005).

Almost surely, 2^649964781 is an apocalyptic number.

It is an amenable number.

649964781 is a deficient number, since it is larger than the sum of its proper divisors (288873249).

649964781 is a wasteful number, since it uses less digits than its factorization.

649964781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 72218315 (or 72218312 counting only the distinct ones).

The product of its digits is 2612736, while the sum is 54.

The square root of 649964781 is about 25494.4068571912. The cubic root of 649964781 is about 866.2234598916.

The spelling of 649964781 in words is "six hundred forty-nine million, nine hundred sixty-four thousand, seven hundred eighty-one".