667435650821 has 2 divisors, whose sum is σ = 667435650822. Its totient is φ = 667435650820.

The previous prime is 667435650779. The next prime is 667435650883. The reversal of 667435650821 is 128056534766.

It is a happy number.

667435650821 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., 659163748321 + 8271902500 = 811889^2 + 90950^2 .

It is a cyclic number.

It is not a de Polignac number, because 667435650821 - 2⁶ = 667435650757 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (667435850821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333717825410 + 333717825411.

It is an arithmetic number, because the mean of its divisors is an integer number (333717825411).

Almost surely, 2^667435650821 is an apocalyptic number.

It is an amenable number.

667435650821 is a deficient number, since it is larger than the sum of its proper divisors (1).

667435650821 is an equidigital number, since it uses as much as digits as its factorization.

667435650821 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7257600, while the sum is 53.

The spelling of 667435650821 in words is "six hundred sixty-seven billion, four hundred thirty-five million, six hundred fifty thousand, eight hundred twenty-one".