7638685840 has 40 divisors (see below), whose sum is σ = 18372362040. Its totient is φ = 2950112256.

The previous prime is 7638685829. The next prime is 7638685861. The reversal of 7638685840 is 485868367.

It can be written as a sum of positive squares in 4 ways, for example, as 1426723984 + 6211961856 = 37772^2 + 78816^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is a Smith number, since the sum of its digits (55) coincides with the sum of the digits of its prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1643949 + ... + 1648588.

It is an arithmetic number, because the mean of its divisors is an integer number (459309051).

Almost surely, 2^7638685840 is an apocalyptic number.

It is an amenable number.

7638685840 is an abundant number, since it is smaller than the sum of its proper divisors (10733676200).

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

7638685840 is a wasteful number, since it uses less digits than its factorization.

7638685840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3292579 (or 3292573 counting only the distinct ones).

The product of its (nonzero) digits is 7741440, while the sum is 55.

The square root of 7638685840 is about 87399.5757426774. The cubic root of 7638685840 is about 1969.4254674063.

The spelling of 7638685840 in words is "seven billion, six hundred thirty-eight million, six hundred eighty-five thousand, eight hundred forty".