687391920 has 400 divisors, whose sum is σ = 2545158528. Its totient is φ = 171694080.

The previous prime is 687391909. The next prime is 687391951. The reversal of 687391920 is 29193786.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 11268690 + ... + 11268750.

Almost surely, 2^687391920 is an apocalyptic number.

687391920 is a gapful number since it is divisible by the number (60) 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 687391920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1272579264).

687391920 is an abundant number, since it is smaller than the sum of its proper divisors (1857766608).

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

687391920 is a wasteful number, since it uses less digits than its factorization.

687391920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 170 (or 155 counting only the distinct ones).

The product of its (nonzero) digits is 163296, while the sum is 45.

The square root of 687391920 is about 26218.1601185133. The cubic root of 687391920 is about 882.5408317049.

The spelling of 687391920 in words is "six hundred eighty-seven million, three hundred ninety-one thousand, nine hundred twenty".