1688029861 has 6 divisors (see below), whose sum is σ = 1963626630. Its totient is φ = 1446882696.

The previous prime is 1688029859. The next prime is 1688029877. The reversal of 1688029861 is 1689208861.

It can be written as a sum of positive squares in only one way, i.e., 1140750625 + 547279236 = 33775^2 + 23394^2 .

It is not a de Polignac number, because 1688029861 - 2¹ = 1688029859 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (49), and also a Moran number because the ratio is a prime number: 34449589 = 1688029861 / (1 + 6 + 8 + 8 + 0 + 2 + 9 + 8 + 6 + 1).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1688029891) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 17224746 + ... + 17224843.

It is an arithmetic number, because the mean of its divisors is an integer number (327271105).

Almost surely, 2^1688029861 is an apocalyptic number.

It is an amenable number.

1688029861 is a deficient number, since it is larger than the sum of its proper divisors (275596769).

1688029861 is an equidigital number, since it uses as much as digits as its factorization.

1688029861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34449603 (or 34449596 counting only the distinct ones).

The product of its (nonzero) digits is 331776, while the sum is 49.

The square root of 1688029861 is about 41085.6405694252. The cubic root of 1688029861 is about 1190.6753836267.

The spelling of 1688029861 in words is "one billion, six hundred eighty-eight million, twenty-nine thousand, eight hundred sixty-one".