1981264 has 10 divisors (see below), whose sum is σ = 3838730. Its totient is φ = 990624.

The previous prime is 1981247. The next prime is 1981267. The reversal of 1981264 is 4621891.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 1710864 + 270400 = 1308^2 + 520^2 .

It is a super-3 number, since 3×1981264³ = 23331802947401183232, which contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1981267) 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 as a sum of consecutive naturals, namely, 61899 + ... + 61930.

It is an arithmetic number, because the mean of its divisors is an integer number (383873).

2^1981264 is an apocalyptic number.

It is an amenable number.

1981264 is a deficient number, since it is larger than the sum of its proper divisors (1857466).

1981264 is a wasteful number, since it uses less digits than its factorization.

1981264 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 123837 (or 123831 counting only the distinct ones).

The product of its digits is 3456, while the sum is 31.

The square root of 1981264 is about 1407.5737991310. The cubic root of 1981264 is about 125.5974386539.

The spelling of 1981264 in words is "one million, nine hundred eighty-one thousand, two hundred sixty-four".