6698978640 has 100 divisors (see below), whose sum is σ = 23266567764. Its totient is φ = 1786392576.

The previous prime is 6698978633. The next prime is 6698978659. The reversal of 6698978640 is 468798966.

It can be written as a sum of positive squares in 2 ways, for example, as 4019052816 + 2679925824 = 63396^2 + 51768^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 510417 + ... + 523376.

Almost surely, 2^6698978640 is an apocalyptic number.

6698978640 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

6698978640 is an abundant number, since it is smaller than the sum of its proper divisors (16567589124).

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

6698978640 is a wasteful number, since it uses less digits than its factorization.

6698978640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1033818 (or 1033803 counting only the distinct ones).

The product of its (nonzero) digits is 31352832, while the sum is 63.

The square root of 6698978640 is about 81847.2885317528. The cubic root of 6698978640 is about 1885.1078315469.

The spelling of 6698978640 in words is "six billion, six hundred ninety-eight million, nine hundred seventy-eight thousand, six hundred forty".