1381556565 has 48 divisors (see below), whose sum is σ = 2447997552. Its totient is φ = 720525312.

The previous prime is 1381556521. The next prime is 1381556581. The reversal of 1381556565 is 5656551831.

1381556565 is a `hidden beast` number, since 1 + 3 + 81 + 5 + 5 + 6 + 565 = 666.

It can be written as a sum of positive squares in 8 ways, for example, as 37380996 + 1344175569 = 6114^2 + 36663^2 .

It is not a de Polignac number, because 1381556565 - 2⁷ = 1381556437 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 1381556565.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 888829 + ... + 890381.

It is an arithmetic number, because the mean of its divisors is an integer number (50999949).

Almost surely, 2^1381556565 is an apocalyptic number.

1381556565 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1381556565 is a deficient number, since it is larger than the sum of its proper divisors (1066440987).

1381556565 is a wasteful number, since it uses less digits than its factorization.

1381556565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1990 (or 1987 counting only the distinct ones).

The product of its digits is 540000, while the sum is 45.

The square root of 1381556565 is about 37169.2959981757. The cubic root of 1381556565 is about 1113.7547185084.

The spelling of 1381556565 in words is "one billion, three hundred eighty-one million, five hundred fifty-six thousand, five hundred sixty-five".