649875581 has 2 divisors, whose sum is σ = 649875582. Its totient is φ = 649875580.

The previous prime is 649875509. The next prime is 649875607. The reversal of 649875581 is 185578946.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 637562500 + 12313081 = 25250^2 + 3509^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-649875581 is a prime.

It is a super-2 number, since 2×649875581² = 844676541560175122, 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 (649872581) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 324937790 + 324937791.

It is an arithmetic number, because the mean of its divisors is an integer number (324937791).

Almost surely, 2^649875581 is an apocalyptic number.

It is an amenable number.

649875581 is a deficient number, since it is larger than the sum of its proper divisors (1).

649875581 is an equidigital number, since it uses as much as digits as its factorization.

649875581 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2419200, while the sum is 53.

The square root of 649875581 is about 25492.6573938458. The cubic root of 649875581 is about 866.1838317611.

The spelling of 649875581 in words is "six hundred forty-nine million, eight hundred seventy-five thousand, five hundred eighty-one".