1381664 has 12 divisors (see below), whose sum is σ = 2720214. Its totient is φ = 690816.

The previous prime is 1381649. The next prime is 1381693. The reversal of 1381664 is 4661831.

It can be written as a sum of positive squares in only one way, i.e., 1123600 + 258064 = 1060^2 + 508^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21557 + ... + 21620.

2^1381664 is an apocalyptic number.

It is an amenable number.

1381664 is a deficient number, since it is larger than the sum of its proper divisors (1338550).

1381664 is an equidigital number, since it uses as much as digits as its factorization.

1381664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43187 (or 43179 counting only the distinct ones).

The product of its digits is 3456, while the sum is 29.

The square root of 1381664 is about 1175.4420445092. The cubic root of 1381664 is about 111.3783587669.

The spelling of 1381664 in words is "one million, three hundred eighty-one thousand, six hundred sixty-four".