678664215121536 has 384 divisors, whose sum is σ = 2315090313768960. Its totient is φ = 193861319777280.

The previous prime is 678664215121517. The next prime is 678664215121547. The reversal of 678664215121536 is 635121512466876.

678664215121536 is a `hidden beast` number, since 6 + 7 + 8 + 6 + 6 + 4 + 21 + 51 + 21 + 536 = 666.

It is a tau number, because it is divible by the number of its divisors (384).

It is a Harshad number since it is a multiple of its sum of digits (63).

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 994022521 + ... + 994705031.

It is an arithmetic number, because the mean of its divisors is an integer number (6028881025440).

Almost surely, 2^{678664215121536} 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 678664215121536, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1157545156884480).

678664215121536 is an abundant number, since it is smaller than the sum of its proper divisors (1636426098647424).

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

678664215121536 is an equidigital number, since it uses as much as digits as its factorization.

678664215121536 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 687114 (or 687090 counting only the distinct ones).

The product of its digits is 87091200, while the sum is 63.

The spelling of 678664215121536 in words is "six hundred seventy-eight trillion, six hundred sixty-four billion, two hundred fifteen million, one hundred twenty-one thousand, five hundred thirty-six".