668682055649 has 2 divisors, whose sum is σ = 668682055650. Its totient is φ = 668682055648.

The previous prime is 668682055637. The next prime is 668682055687. The reversal of 668682055649 is 946550286866.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 366336036049 + 302346019600 = 605257^2 + 549860^2 .

It is a cyclic number.

It is not a de Polignac number, because 668682055649 - 2⁴ = 668682055633 is a prime.

It is a super-2 number, since 2×668682055649² (a number of 24 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (668682055609) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 334341027824 + 334341027825.

It is an arithmetic number, because the mean of its divisors is an integer number (334341027825).

Almost surely, 2^668682055649 is an apocalyptic number.

It is an amenable number.

668682055649 is a deficient number, since it is larger than the sum of its proper divisors (1).

668682055649 is an equidigital number, since it uses as much as digits as its factorization.

668682055649 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 149299200, while the sum is 65.

The spelling of 668682055649 in words is "six hundred sixty-eight billion, six hundred eighty-two million, fifty-five thousand, six hundred forty-nine".