11531565 has 24 divisors (see below), whose sum is σ = 20730528. Its totient is φ = 6149520.

The previous prime is 11531563. The next prime is 11531567. The reversal of 11531565 is 56513511.

It is an interprime number because it is at equal distance from previous prime (11531563) and next prime (11531567).

It is not a de Polignac number, because 11531565 - 2¹ = 11531563 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11531561) 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, 3531 + ... + 5960.

It is an arithmetic number, because the mean of its divisors is an integer number (863772).

Almost surely, 2^11531565 is an apocalyptic number.

11531565 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

11531565 is a deficient number, since it is larger than the sum of its proper divisors (9198963).

11531565 is an frugal number, since it uses more digits than its factorization.

11531565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9511 (or 9499 counting only the distinct ones).

The product of its digits is 2250, while the sum is 27.

The square root of 11531565 is about 3395.8158077257. The cubic root of 11531565 is about 225.9241986109.

The spelling of 11531565 in words is "eleven million, five hundred thirty-one thousand, five hundred sixty-five".