1660686649 has 2 divisors, whose sum is σ = 1660686650. Its totient is φ = 1660686648.

The previous prime is 1660686619. The next prime is 1660686679. The reversal of 1660686649 is 9466860661.

It is a balanced prime because it is at equal distance from previous prime (1660686619) and next prime (1660686679).

It can be written as a sum of positive squares in only one way, i.e., 1369370025 + 291316624 = 37005^2 + 17068^2 .

It is an emirp because it is prime and its reverse (9466860661) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1660686649 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1660686596 and 1660686605.

It is not a weakly prime, because it can be changed into another prime (1660686619) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 830343324 + 830343325.

It is an arithmetic number, because the mean of its divisors is an integer number (830343325).

Almost surely, 2^1660686649 is an apocalyptic number.

It is an amenable number.

1660686649 is a deficient number, since it is larger than the sum of its proper divisors (1).

1660686649 is an equidigital number, since it uses as much as digits as its factorization.

1660686649 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2239488, while the sum is 52.

The square root of 1660686649 is about 40751.5232721428. The cubic root of 1660686649 is about 1184.2113831656.

The spelling of 1660686649 in words is "one billion, six hundred sixty million, six hundred eighty-six thousand, six hundred forty-nine".