686059978 has 4 divisors (see below), whose sum is σ = 1029089970. Its totient is φ = 343029988.

The previous prime is 686059963. The next prime is 686059993. The reversal of 686059978 is 879950686.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (686059963) and next prime (686059993).

It can be written as a sum of positive squares in only one way, i.e., 655001649 + 31058329 = 25593^2 + 5573^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 171514993 + ... + 171514996.

Almost surely, 2^686059978 is an apocalyptic number.

686059978 is a deficient number, since it is larger than the sum of its proper divisors (343029992).

686059978 is a wasteful number, since it uses less digits than its factorization.

686059978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 343029991.

The product of its (nonzero) digits is 6531840, while the sum is 58.

The square root of 686059978 is about 26192.7466677323. The cubic root of 686059978 is about 881.9704374239.

The spelling of 686059978 in words is "six hundred eighty-six million, fifty-nine thousand, nine hundred seventy-eight".