1620820 has 12 divisors (see below), whose sum is σ = 3403764. Its totient is φ = 648320.

The previous prime is 1620811. The next prime is 1620823. The reversal of 1620820 is 280261.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 725904 + 894916 = 852^2 + 946^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1620823) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 40501 + ... + 40540.

It is an arithmetic number, because the mean of its divisors is an integer number (283647).

2^1620820 is an apocalyptic number.

1620820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1620820 is an abundant number, since it is smaller than the sum of its proper divisors (1782944).

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

1620820 is a wasteful number, since it uses less digits than its factorization.

1620820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81050 (or 81048 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 19.

The square root of 1620820 is about 1273.1142918057. The cubic root of 1620820 is about 117.4658418893.

The spelling of 1620820 in words is "one million, six hundred twenty thousand, eight hundred twenty".