634540661 has 2 divisors, whose sum is σ = 634540662. Its totient is φ = 634540660.

The previous prime is 634540649. The next prime is 634540679. The reversal of 634540661 is 166045436.

634540661 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 532732561 + 101808100 = 23081^2 + 10090^2 .

It is a cyclic number.

It is not a de Polignac number, because 634540661 - 2⁶ = 634540597 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (634540631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 317270330 + 317270331.

It is an arithmetic number, because the mean of its divisors is an integer number (317270331).

Almost surely, 2^634540661 is an apocalyptic number.

It is an amenable number.

634540661 is a deficient number, since it is larger than the sum of its proper divisors (1).

634540661 is an equidigital number, since it uses as much as digits as its factorization.

634540661 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 35.

The square root of 634540661 is about 25190.0905317944. The cubic root of 634540661 is about 859.3165026249.

The spelling of 634540661 in words is "six hundred thirty-four million, five hundred forty thousand, six hundred sixty-one".