1381639 has 8 divisors (see below), whose sum is σ = 1630208. Its totient is φ = 1145880.

The previous prime is 1381637. The next prime is 1381643. The reversal of 1381639 is 9361831.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1381639 - 2¹ = 1381637 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (31).

It is an Ulam number.

It is a Duffinian number.

1381639 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 1381639.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1381637) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2967 + ... + 3400.

It is an arithmetic number, because the mean of its divisors is an integer number (203776).

2^1381639 is an apocalyptic number.

1381639 is a deficient number, since it is larger than the sum of its proper divisors (248569).

1381639 is an equidigital number, since it uses as much as digits as its factorization.

1381639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6405.

The product of its digits is 3888, while the sum is 31.

The square root of 1381639 is about 1175.4314101639. The cubic root of 1381639 is about 111.3776869983.

The spelling of 1381639 in words is "one million, three hundred eighty-one thousand, six hundred thirty-nine".