1981504 has 28 divisors (see below), whose sum is σ = 4494784. Its totient is φ = 849024.

The previous prime is 1981493. The next prime is 1981513. The reversal of 1981504 is 4051891.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (28).

It is a Harshad number since it is a multiple of its sum of digits (28).

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1764 + ... + 2659.

It is an arithmetic number, because the mean of its divisors is an integer number (160528).

2^1981504 is an apocalyptic number.

1981504 is a gapful number since it is divisible by the number (14) formed by its first and last digit.

It is an amenable number.

1981504 is an abundant number, since it is smaller than the sum of its proper divisors (2513280).

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

1981504 is an equidigital number, since it uses as much as digits as its factorization.

1981504 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4442 (or 4432 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 28.

The square root of 1981504 is about 1407.6590496281. The cubic root of 1981504 is about 125.6025098556.

It can be divided in two parts, 1981 and 504, that added together give a triangular number (2485 = T₇₀).

The spelling of 1981504 in words is "one million, nine hundred eighty-one thousand, five hundred four".