1688720740 has 48 divisors (see below), whose sum is σ = 4069828224. Its totient is φ = 576576000.

The previous prime is 1688720717. The next prime is 1688720749. The reversal of 1688720740 is 470278861.

It is a super-2 number, since 2×1688720740² = 5703555475412295200, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1688720749) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8715 + ... + 58765.

It is an arithmetic number, because the mean of its divisors is an integer number (84788088).

Almost surely, 2^1688720740 is an apocalyptic number.

1688720740 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1688720740, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2034914112).

1688720740 is an abundant number, since it is smaller than the sum of its proper divisors (2381107484).

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

1688720740 is a wasteful number, since it uses less digits than its factorization.

1688720740 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50308 (or 50306 counting only the distinct ones).

The product of its (nonzero) digits is 150528, while the sum is 43.

The square root of 1688720740 is about 41094.0475008243. The cubic root of 1688720740 is about 1190.8378018469.

The spelling of 1688720740 in words is "one billion, six hundred eighty-eight million, seven hundred twenty thousand, seven hundred forty".