687434779654656 has 320 divisors, whose sum is σ = 2027853642203136. Its totient is φ = 205191279820800.

The previous prime is 687434779654607. The next prime is 687434779654681. The reversal of 687434779654656 is 656456977434786.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1310918145 + ... + 1311442431.

Almost surely, 2^{687434779654656} is an apocalyptic number.

687434779654656 is a gapful number since it is divisible by the number (66) 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 687434779654656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1013926821101568).

687434779654656 is an abundant number, since it is smaller than the sum of its proper divisors (1340418862548480).

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

687434779654656 is a wasteful number, since it uses less digits than its factorization.

687434779654656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 525483 (or 525467 counting only the distinct ones).

The product of its digits is 153628876800, while the sum is 87.

The spelling of 687434779654656 in words is "six hundred eighty-seven trillion, four hundred thirty-four billion, seven hundred seventy-nine million, six hundred fifty-four thousand, six hundred fifty-six".