1689657972979 has 2 divisors, whose sum is σ = 1689657972980. Its totient is φ = 1689657972978.

The previous prime is 1689657972941. The next prime is 1689657973021. The reversal of 1689657972979 is 9792797569861.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1689657972979 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1689657972896 and 1689657972905.

It is not a weakly prime, because it can be changed into another prime (1689657972929) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 844828986489 + 844828986490.

It is an arithmetic number, because the mean of its divisors is an integer number (844828986490).

Almost surely, 2^{1689657972979} is an apocalyptic number.

1689657972979 is a deficient number, since it is larger than the sum of its proper divisors (1).

1689657972979 is an equidigital number, since it uses as much as digits as its factorization.

1689657972979 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6481218240, while the sum is 85.

The spelling of 1689657972979 in words is "one trillion, six hundred eighty-nine billion, six hundred fifty-seven million, nine hundred seventy-two thousand, nine hundred seventy-nine".