1640680 has 16 divisors (see below), whose sum is σ = 3691620. Its totient is φ = 656256.

The previous prime is 1640677. The next prime is 1640689. The reversal of 1640680 is 860461.

It can be written as a sum of positive squares in 2 ways, for example, as 1633284 + 7396 = 1278^2 + 86^2 .

It is an Ulam number.

It is not an unprimeable number, because it can be changed into a prime (1640689) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20469 + ... + 20548.

2^1640680 is an apocalyptic number.

1640680 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1640680 is an abundant number, since it is smaller than the sum of its proper divisors (2050940).

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

1640680 is a wasteful number, since it uses less digits than its factorization.

1640680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41028 (or 41024 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 25.

The square root of 1640680 is about 1280.8903153666. The cubic root of 1640680 is about 117.9436674521.

The spelling of 1640680 in words is "one million, six hundred forty thousand, six hundred eighty".