686776838400 has 405 divisors, whose sum is σ = 2541534998233. Its totient is φ = 182981376000.

The previous prime is 686776838393. The next prime is 686776838437. The reversal of 686776838400 is 4838677686.

The square root of 686776838400 is 828720.

It is a perfect power (a square), and thus also a powerful number.

686776838400 is a `hidden beast` number, since 6 + 86 + 7 + 76 + 83 + 8 + 400 = 666.

686776838400 is digitally balanced in base 2 and base 4, because in such bases it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 247239661824 + 439537176576 = 497232^2 + 662976^2 .

It is a tau number, because it is divible by the number of its divisors (405).

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 44 ways as a sum of consecutive naturals, for example, 596677825 + ... + 596678975.

Almost surely, 2^686776838400 is an apocalyptic number.

686776838400 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

686776838400 is the 828720-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 686776838400

686776838400 is an abundant number, since it is smaller than the sum of its proper divisors (1854758159833).

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

686776838400 is an frugal number, since it uses more digits than its factorization.

686776838400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2340 (or 1161 counting only the distinct ones).

The product of its (nonzero) digits is 65028096, while the sum is 63.

The spelling of 686776838400 in words is "six hundred eighty-six billion, seven hundred seventy-six million, eight hundred thirty-eight thousand, four hundred".