65634380921 has 2 divisors, whose sum is σ = 65634380922. Its totient is φ = 65634380920.

The previous prime is 65634380891. The next prime is 65634380927. The reversal of 65634380921 is 12908343656.

65634380921 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 43555690000 + 22078690921 = 208700^2 + 148589^2 .

It is a cyclic number.

It is not a de Polignac number, because 65634380921 - 2¹⁰ = 65634379897 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (65634380927) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32817190460 + 32817190461.

It is an arithmetic number, because the mean of its divisors is an integer number (32817190461).

Almost surely, 2^65634380921 is an apocalyptic number.

It is an amenable number.

65634380921 is a deficient number, since it is larger than the sum of its proper divisors (1).

65634380921 is an equidigital number, since it uses as much as digits as its factorization.

65634380921 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 933120, while the sum is 47.

The spelling of 65634380921 in words is "sixty-five billion, six hundred thirty-four million, three hundred eighty thousand, nine hundred twenty-one".