1620640 has 48 divisors (see below), whose sum is σ = 4378752. Its totient is φ = 555264.

The previous prime is 1620631. The next prime is 1620667. The reversal of 1620640 is 460261.

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, 397 + ... + 1843.

It is an arithmetic number, because the mean of its divisors is an integer number (91224).

2^1620640 is an apocalyptic number.

1620640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1620640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2189376).

1620640 is an abundant number, since it is smaller than the sum of its proper divisors (2758112).

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

1620640 is a wasteful number, since it uses less digits than its factorization.

1620640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1469 (or 1461 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 19.

The square root of 1620640 is about 1273.0435970539. The cubic root of 1620640 is about 117.4614933426.

The spelling of 1620640 in words is "one million, six hundred twenty thousand, six hundred forty".