686378052 has 72 divisors (see below), whose sum is σ = 1815952320. Its totient is φ = 218180160.

The previous prime is 686377987. The next prime is 686378071. The reversal of 686378052 is 250873686.

686378052 is a `hidden beast` number, since 6 + 8 + 637 + 8 + 0 + 5 + 2 = 666.

It is a super-2 number, since 2×686378052² = 942229660534629408, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 686377989 and 686378007.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 321027 + ... + 323157.

It is an arithmetic number, because the mean of its divisors is an integer number (25221560).

Almost surely, 2^686378052 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 686378052, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (907976160).

686378052 is an abundant number, since it is smaller than the sum of its proper divisors (1129574268).

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

686378052 is a wasteful number, since it uses less digits than its factorization.

686378052 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2553 (or 2548 counting only the distinct ones).

The product of its (nonzero) digits is 483840, while the sum is 45.

The square root of 686378052 is about 26198.8177595860. The cubic root of 686378052 is about 882.1067173077.

The spelling of 686378052 in words is "six hundred eighty-six million, three hundred seventy-eight thousand, fifty-two".