634540649 has 2 divisors, whose sum is σ = 634540650. Its totient is φ = 634540648.

The previous prime is 634540631. The next prime is 634540661. The reversal of 634540649 is 946045436.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 362521600 + 272019049 = 19040^2 + 16493^2 .

It is a cyclic number.

It is not a de Polignac number, because 634540649 - 2⁸ = 634540393 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 (634540609) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 317270324 + 317270325.

It is an arithmetic number, because the mean of its divisors is an integer number (317270325).

Almost surely, 2^634540649 is an apocalyptic number.

It is an amenable number.

634540649 is a deficient number, since it is larger than the sum of its proper divisors (1).

634540649 is an equidigital number, since it uses as much as digits as its factorization.

634540649 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 311040, while the sum is 41.

The square root of 634540649 is about 25190.0902936055. The cubic root of 634540649 is about 859.3164972080.

The spelling of 634540649 in words is "six hundred thirty-four million, five hundred forty thousand, six hundred forty-nine".