1981861596 has 144 divisors (see below), whose sum is σ = 6011486208. Its totient is φ = 542505600.

The previous prime is 1981861577. The next prime is 1981861619. The reversal of 1981861596 is 6951681891.

1981861596 is a `hidden beast` number, since 1 + 9 + 8 + 18 + 615 + 9 + 6 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 237861 + ... + 246051.

It is an arithmetic number, because the mean of its divisors is an integer number (41746432).

Almost surely, 2^1981861596 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1981861596, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3005743104).

1981861596 is an abundant number, since it is smaller than the sum of its proper divisors (4029624612).

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

1981861596 is a wasteful number, since it uses less digits than its factorization.

1981861596 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8272 (or 8267 counting only the distinct ones).

The product of its digits is 933120, while the sum is 54.

The square root of 1981861596 is about 44518.1041375304. The cubic root of 1981861596 is about 1256.1006510209.

The spelling of 1981861596 in words is "one billion, nine hundred eighty-one million, eight hundred sixty-one thousand, five hundred ninety-six".