1688191956 has 84 divisors (see below), whose sum is σ = 4832249184. Its totient is φ = 511563600.

The previous prime is 1688191937. The next prime is 1688191979. The reversal of 1688191956 is 6591918861.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 27 ways as a sum of consecutive naturals, for example, 5761 + ... + 58391.

It is an arithmetic number, because the mean of its divisors is an integer number (57526776).

Almost surely, 2^1688191956 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1688191956, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2416124592).

1688191956 is an abundant number, since it is smaller than the sum of its proper divisors (3144057228).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1688191956 is a wasteful number, since it uses less digits than its factorization.

1688191956 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52664 (or 52647 counting only the distinct ones).

The product of its digits is 933120, while the sum is 54.

The square root of 1688191956 is about 41087.6131699080. The cubic root of 1688191956 is about 1190.7134943958.

The spelling of 1688191956 in words is "one billion, six hundred eighty-eight million, one hundred ninety-one thousand, nine hundred fifty-six".