688862640 has 80 divisors (see below), whose sum is σ = 2138086368. Its totient is φ = 183472128.

The previous prime is 688862621. The next prime is 688862653. The reversal of 688862640 is 46268886.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a self number, because there is not a number n which added to its sum of digits gives 688862640.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 310174 + ... + 312386.

Almost surely, 2^688862640 is an apocalyptic number.

688862640 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

688862640 is an abundant number, since it is smaller than the sum of its proper divisors (1449223728).

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

688862640 is a wasteful number, since it uses less digits than its factorization.

688862640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3526 (or 3520 counting only the distinct ones).

The product of its (nonzero) digits is 884736, while the sum is 48.

The square root of 688862640 is about 26246.1928667759. The cubic root of 688862640 is about 883.1698013002.

The spelling of 688862640 in words is "six hundred eighty-eight million, eight hundred sixty-two thousand, six hundred forty".