687643912 has 8 divisors (see below), whose sum is σ = 1289332350. Its totient is φ = 343821952.

The previous prime is 687643907. The next prime is 687643933. The reversal of 687643912 is 219346786.

It can be written as a sum of positive squares in only one way, i.e., 681523236 + 6120676 = 26106^2 + 2474^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42977737 + ... + 42977752.

Almost surely, 2^687643912 is an apocalyptic number.

It is an amenable number.

687643912 is a deficient number, since it is larger than the sum of its proper divisors (601688438).

687643912 is a wasteful number, since it uses less digits than its factorization.

687643912 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 85955495 (or 85955491 counting only the distinct ones).

The product of its digits is 435456, while the sum is 46.

The square root of 687643912 is about 26222.9653548183. The cubic root of 687643912 is about 882.6486625035.

The spelling of 687643912 in words is "six hundred eighty-seven million, six hundred forty-three thousand, nine hundred twelve".