1688901691 has 2 divisors, whose sum is σ = 1688901692. Its totient is φ = 1688901690.

The previous prime is 1688901689. The next prime is 1688901701. The reversal of 1688901691 is 1961098861.

It is a happy number.

It is a weak prime.

It is an emirp because it is prime and its reverse (1961098861) is a distict prime. It is also a bemirp because it and its reverse can be mirrored producing other two distinct primes, 1691068891 and 1988601961.

It is a cyclic number.

It is not a de Polignac number, because 1688901691 - 2¹ = 1688901689 is a prime.

Together with 1688901689, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (1688901611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 844450845 + 844450846.

It is an arithmetic number, because the mean of its divisors is an integer number (844450846).

Almost surely, 2^1688901691 is an apocalyptic number.

1688901691 is a deficient number, since it is larger than the sum of its proper divisors (1).

1688901691 is an equidigital number, since it uses as much as digits as its factorization.

1688901691 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 186624, while the sum is 49.

The square root of 1688901691 is about 41096.2491110807. The cubic root of 1688901691 is about 1190.8803341595.

The spelling of 1688901691 in words is "one billion, six hundred eighty-eight million, nine hundred one thousand, six hundred ninety-one".