1381640 has 32 divisors (see below), whose sum is σ = 3349080. Its totient is φ = 509952.

The previous prime is 1381637. The next prime is 1381643. The reversal of 1381640 is 461831.

It is an interprime number because it is at equal distance from previous prime (1381637) and next prime (1381643).

It can be written as a sum of positive squares in 4 ways, for example, as 964324 + 417316 = 982^2 + 646^2 .

It is not an unprimeable number, because it can be changed into a prime (1381643) by changing a digit.

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 in 7 ways as a sum of consecutive naturals, for example, 809 + ... + 1848.

2^1381640 is an apocalyptic number.

1381640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1381640 is an abundant number, since it is smaller than the sum of its proper divisors (1967440).

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

1381640 is a wasteful number, since it uses less digits than its factorization.

1381640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2681 (or 2677 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 23.

The square root of 1381640 is about 1175.4318355396. The cubic root of 1381640 is about 111.3777138692.

The spelling of 1381640 in words is "one million, three hundred eighty-one thousand, six hundred forty".