1687920640 has 252 divisors, whose sum is σ = 4880200806. Its totient is φ = 558759936.

The previous prime is 1687920629. The next prime is 1687920719. The reversal of 1687920640 is 460297861.

It can be written as a sum of positive squares in 3 ways, for example, as 1382649856 + 305270784 = 37184^2 + 17472^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 58204146 + ... + 58204174.

Almost surely, 2^1687920640 is an apocalyptic number.

1687920640 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 1687920640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2440100403).

1687920640 is an abundant number, since it is smaller than the sum of its proper divisors (3192280166).

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

1687920640 is an frugal number, since it uses more digits than its factorization.

1687920640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 103 (or 43 counting only the distinct ones).

The product of its (nonzero) digits is 145152, while the sum is 43.

The square root of 1687920640 is about 41084.3113609076. The cubic root of 1687920640 is about 1190.6497028881.

The spelling of 1687920640 in words is "one billion, six hundred eighty-seven million, nine hundred twenty thousand, six hundred forty".