1381563765 has 24 divisors (see below), whose sum is σ = 2435303520. Its totient is φ = 724343904.

The previous prime is 1381563761. The next prime is 1381563767. The reversal of 1381563765 is 5673651831.

1381563765 is a `hidden beast` number, since 1 + 3 + 8 + 1 + 5 + 637 + 6 + 5 = 666.

It is not a de Polignac number, because 1381563765 - 2² = 1381563761 is a prime.

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

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 1381563765.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1381563761) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 257527 + ... + 262836.

It is an arithmetic number, because the mean of its divisors is an integer number (101470980).

Almost surely, 2^1381563765 is an apocalyptic number.

1381563765 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1381563765 is a deficient number, since it is larger than the sum of its proper divisors (1053739755).

1381563765 is a wasteful number, since it uses less digits than its factorization.

1381563765 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 520433 (or 520430 counting only the distinct ones).

The product of its digits is 453600, while the sum is 45.

The square root of 1381563765 is about 37169.3928521842. The cubic root of 1381563765 is about 1113.7566532874.

The spelling of 1381563765 in words is "one billion, three hundred eighty-one million, five hundred sixty-three thousand, seven hundred sixty-five".