7681640 has 32 divisors (see below), whose sum is σ = 17395560. Its totient is φ = 3052800.

The previous prime is 7681631. The next prime is 7681651. The reversal of 7681640 is 461867.

It can be written as a sum of positive squares in 4 ways, for example, as 4318084 + 3363556 = 2078^2 + 1834^2 .

It is a junction number, because it is equal to n+sod(n) for n = 7681597 and 7681606.

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, 6710 + ... + 7770.

Almost surely, 2^7681640 is an apocalyptic number.

It is an amenable number.

7681640 is an abundant number, since it is smaller than the sum of its proper divisors (9713920).

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

7681640 is a wasteful number, since it uses less digits than its factorization.

7681640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1253 (or 1249 counting only the distinct ones).

The product of its (nonzero) digits is 8064, while the sum is 32.

The square root of 7681640 is about 2771.5771683285. The cubic root of 7681640 is about 197.3110086546.

The spelling of 7681640 in words is "seven million, six hundred eighty-one thousand, six hundred forty".