1981604000 has 48 divisors (see below), whose sum is σ = 4868810856. Its totient is φ = 792640000.

The previous prime is 1981603999. The next prime is 1981604003. The reversal of 1981604000 is 4061891.

It can be written as a sum of positive squares in 4 ways, for example, as 302899216 + 1678704784 = 17404^2 + 40972^2 .

It is not an unprimeable number, because it can be changed into a prime (1981604003) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 243701 + ... + 251700.

Almost surely, 2^1981604000 is an apocalyptic number.

1981604000 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1981604000 is an abundant number, since it is smaller than the sum of its proper divisors (2887206856).

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

1981604000 is an equidigital number, since it uses as much as digits as its factorization.

1981604000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 495426 (or 495408 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 29.

The square root of 1981604000 is about 44515.2108834722. The cubic root of 1981604000 is about 1256.0462273545.

Adding to 1981604000 its reverse (4061891), we get a palindrome (1985665891).

The spelling of 1981604000 in words is "one billion, nine hundred eighty-one million, six hundred four thousand".