1641820 has 24 divisors (see below), whose sum is σ = 3485664. Its totient is φ = 649536.

The previous prime is 1641817. The next prime is 1641821. The reversal of 1641820 is 281461.

It is a junction number, because it is equal to n+sod(n) for n = 1641791 and 1641800.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1641821) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1662 + ... + 2458.

It is an arithmetic number, because the mean of its divisors is an integer number (145236).

2^1641820 is an apocalyptic number.

1641820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1641820 is an abundant number, since it is smaller than the sum of its proper divisors (1843844).

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

1641820 is a wasteful number, since it uses less digits than its factorization.

1641820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 909 (or 907 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 22.

The square root of 1641820 is about 1281.3352410669. The cubic root of 1641820 is about 117.9709782118.

It can be divided in two parts, 1641 and 820, that multiplied together give a triangular number (1345620 = T₁₆₄₀).

The spelling of 1641820 in words is "one million, six hundred forty-one thousand, eight hundred twenty".