1871198820 has 60 divisors (see below), whose sum is σ = 5870025084. Its totient is φ = 498985920.

The previous prime is 1871198809. The next prime is 1871198863. The reversal of 1871198820 is 288911781.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 398481444 + 1472717376 = 19962^2 + 38376^2 .

It is a tau number, because it is divible by the number of its divisors (60).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 575911 + ... + 579150.

Almost surely, 2^1871198820 is an apocalyptic number.

1871198820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1871198820 is an abundant number, since it is smaller than the sum of its proper divisors (3998826264).

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

1871198820 is a wasteful number, since it uses less digits than its factorization.

1871198820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1155082 (or 1155071 counting only the distinct ones).

The product of its (nonzero) digits is 64512, while the sum is 45.

The square root of 1871198820 is about 43257.3556750757. The cubic root of 1871198820 is about 1232.2721831092.

The spelling of 1871198820 in words is "one billion, eight hundred seventy-one million, one hundred ninety-eight thousand, eight hundred twenty".