687400640 has 28 divisors (see below), whose sum is σ = 1636873536. Its totient is φ = 274960128.

The previous prime is 687400613. The next prime is 687400657. The reversal of 687400640 is 46004786.

It is a self number, because there is not a number n which added to its sum of digits gives 687400640.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1073744 + ... + 1074383.

Almost surely, 2^687400640 is an apocalyptic number.

It is an amenable number.

687400640 is an abundant number, since it is smaller than the sum of its proper divisors (949472896).

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

687400640 is a wasteful number, since it uses less digits than its factorization.

687400640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2148144 (or 2148134 counting only the distinct ones).

The product of its (nonzero) digits is 32256, while the sum is 35.

The square root of 687400640 is about 26218.3264149335. The cubic root of 687400640 is about 882.5445635515.

The spelling of 687400640 in words is "six hundred eighty-seven million, four hundred thousand, six hundred forty".