1688830021 has 2 divisors, whose sum is σ = 1688830022. Its totient is φ = 1688830020.

The previous prime is 1688829973. The next prime is 1688830061. The reversal of 1688830021 is 1200388861.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1240025796 + 448804225 = 35214^2 + 21185^2 .

It is a cyclic number.

It is not a de Polignac number, because 1688830021 - 2¹³ = 1688821829 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1688830061) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 844415010 + 844415011.

It is an arithmetic number, because the mean of its divisors is an integer number (844415011).

Almost surely, 2^1688830021 is an apocalyptic number.

It is an amenable number.

1688830021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1688830021 is an equidigital number, since it uses as much as digits as its factorization.

1688830021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 18432, while the sum is 37.

The square root of 1688830021 is about 41095.3771244407. The cubic root of 1688830021 is about 1190.8634885765.

The spelling of 1688830021 in words is "one billion, six hundred eighty-eight million, eight hundred thirty thousand, twenty-one".