1640220 has 24 divisors (see below), whose sum is σ = 4592784. Its totient is φ = 437376.

The previous prime is 1640207. The next prime is 1640231. The reversal of 1640220 is 220461.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 1640220.

It is a congruent number.

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, 13609 + ... + 13728.

It is an arithmetic number, because the mean of its divisors is an integer number (191366).

2^1640220 is an apocalyptic number.

1640220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1640220 is an abundant number, since it is smaller than the sum of its proper divisors (2952564).

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

1640220 is a wasteful number, since it uses less digits than its factorization.

1640220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27349 (or 27347 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 15.

The square root of 1640220 is about 1280.7107401752. The cubic root of 1640220 is about 117.9326437387.

Adding to 1640220 its reverse (220461), we get a palindrome (1860681).

The spelling of 1640220 in words is "one million, six hundred forty thousand, two hundred twenty".