1987820 has 12 divisors (see below), whose sum is σ = 4174464. Its totient is φ = 795120.

The previous prime is 1987819. The next prime is 1987829. The reversal of 1987820 is 287891.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (1987829) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 49676 + ... + 49715.

It is an arithmetic number, because the mean of its divisors is an integer number (347872).

2^1987820 is an apocalyptic number.

1987820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1987820 is an abundant number, since it is smaller than the sum of its proper divisors (2186644).

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

1987820 is a wasteful number, since it uses less digits than its factorization.

1987820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 99400 (or 99398 counting only the distinct ones).

The product of its (nonzero) digits is 8064, while the sum is 35.

The square root of 1987820 is about 1409.9007057236. The cubic root of 1987820 is about 125.7358200517.

The spelling of 1987820 in words is "one million, nine hundred eighty-seven thousand, eight hundred twenty".