1961820 has 120 divisors (see below), whose sum is σ = 7074144. Its totient is φ = 445824.

The previous prime is 1961819. The next prime is 1961833. The reversal of 1961820 is 281691.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 11254 + ... + 11426.

2^1961820 is an apocalyptic number.

1961820 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 1961820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3537072).

1961820 is an abundant number, since it is smaller than the sum of its proper divisors (5112324).

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

1961820 is a wasteful number, since it uses less digits than its factorization.

1961820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 201 (or 190 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 27.

The square root of 1961820 is about 1400.6498491772. The cubic root of 1961820 is about 125.1852187499.

It can be divided in two parts, 196 and 1820, that added together give a triangular number (2016 = T₆₃).

The spelling of 1961820 in words is "one million, nine hundred sixty-one thousand, eight hundred twenty".