1981615104 has 220 divisors, whose sum is σ = 6764827344. Its totient is φ = 566009856.

The previous prime is 1981615079. The next prime is 1981615109. The reversal of 1981615104 is 4015161891.

It is a happy number.

1981615104 is a `hidden beast` number, since 1 + 9 + 81 + 61 + 510 + 4 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (1981615109) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 578902 + ... + 582314.

Almost surely, 2^1981615104 is an apocalyptic number.

1981615104 is a gapful number since it is divisible by the number (14) 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 1981615104, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3382413672).

1981615104 is an abundant number, since it is smaller than the sum of its proper divisors (4783212240).

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

1981615104 is an equidigital number, since it uses as much as digits as its factorization.

1981615104 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3452 (or 3425 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 36.

The square root of 1981615104 is about 44515.3356047104. The cubic root of 1981615104 is about 1256.0485734525.

Adding to 1981615104 its reverse (4015161891), we get a palindrome (5996776995).

The spelling of 1981615104 in words is "one billion, nine hundred eighty-one million, six hundred fifteen thousand, one hundred four".