1213565 has 4 divisors (see below), whose sum is σ = 1456284. Its totient is φ = 970848.

The previous prime is 1213561. The next prime is 1213573. The reversal of 1213565 is 5653121.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 177241 + 1036324 = 421^2 + 1018^2 .

It is a cyclic number.

It is not a de Polignac number, because 1213565 - 2² = 1213561 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1213565.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1213561) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 121352 + ... + 121361.

It is an arithmetic number, because the mean of its divisors is an integer number (364071).

2^1213565 is an apocalyptic number.

It is an amenable number.

1213565 is a deficient number, since it is larger than the sum of its proper divisors (242719).

1213565 is an equidigital number, since it uses as much as digits as its factorization.

1213565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 242718.

The product of its digits is 900, while the sum is 23.

The square root of 1213565 is about 1101.6192627219. The cubic root of 1213565 is about 106.6647731869.

Adding to 1213565 its reverse (5653121), we get a palindrome (6866686).

The spelling of 1213565 in words is "one million, two hundred thirteen thousand, five hundred sixty-five".