687500666 has 4 divisors (see below), whose sum is σ = 1031251002. Its totient is φ = 343750332.

The previous prime is 687500629. The next prime is 687500677. The reversal of 687500666 is 666005786.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 666005786 = 2 ⋅333002893.

It can be written as a sum of positive squares in only one way, i.e., 662290225 + 25210441 = 25735^2 + 5021^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 171875165 + ... + 171875168.

Almost surely, 2^687500666 is an apocalyptic number.

687500666 is a deficient number, since it is larger than the sum of its proper divisors (343750336).

687500666 is a wasteful number, since it uses less digits than its factorization.

687500666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 343750335.

The product of its (nonzero) digits is 362880, while the sum is 44.

The square root of 687500666 is about 26220.2339043724. The cubic root of 687500666 is about 882.5873688268.

The spelling of 687500666 in words is "six hundred eighty-seven million, five hundred thousand, six hundred sixty-six".