1381981643 has 16 divisors (see below), whose sum is σ = 1663641600. Its totient is φ = 1146335400.

The previous prime is 1381981639. The next prime is 1381981649. The reversal of 1381981643 is 3461891831.

It is not a de Polignac number, because 1381981643 - 2² = 1381981639 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1381981594 and 1381981603.

It is not an unprimeable number, because it can be changed into a prime (1381981649) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 54353 + ... + 75618.

It is an arithmetic number, because the mean of its divisors is an integer number (103977600).

Almost surely, 2^1381981643 is an apocalyptic number.

1381981643 is a deficient number, since it is larger than the sum of its proper divisors (281659957).

1381981643 is an equidigital number, since it uses as much as digits as its factorization.

1381981643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 130023 (or 130009 counting only the distinct ones).

The product of its digits is 124416, while the sum is 44.

The square root of 1381981643 is about 37175.0136919948. The cubic root of 1381981643 is about 1113.8689336608.

The spelling of 1381981643 in words is "one billion, three hundred eighty-one million, nine hundred eighty-one thousand, six hundred forty-three".