16678309657 has 2 divisors, whose sum is σ = 16678309658. Its totient is φ = 16678309656.

The previous prime is 16678309651. The next prime is 16678309667. The reversal of 16678309657 is 75690387661.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15411732736 + 1266576921 = 124144^2 + 35589^2 .

It is a cyclic number.

It is not a de Polignac number, because 16678309657 - 2²⁷ = 16544091929 is a prime.

It is not a weakly prime, because it can be changed into another prime (16678309651) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8339154828 + 8339154829.

It is an arithmetic number, because the mean of its divisors is an integer number (8339154829).

Almost surely, 2^16678309657 is an apocalyptic number.

It is an amenable number.

16678309657 is a deficient number, since it is larger than the sum of its proper divisors (1).

16678309657 is an equidigital number, since it uses as much as digits as its factorization.

16678309657 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 11430720, while the sum is 58.

The spelling of 16678309657 in words is "sixteen billion, six hundred seventy-eight million, three hundred nine thousand, six hundred fifty-seven".