1221539 has 4 divisors (see below), whose sum is σ = 1332600. Its totient is φ = 1110480.

The previous prime is 1221533. The next prime is 1221541. The reversal of 1221539 is 9351221.

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

It is a cyclic number.

It is not a de Polignac number, because 1221539 - 2⁴ = 1221523 is a prime.

It is a Duffinian number.

It is a plaindrome in base 12.

It is not an unprimeable number, because it can be changed into a prime (1221533) 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, 55514 + ... + 55535.

It is an arithmetic number, because the mean of its divisors is an integer number (333150).

2^1221539 is an apocalyptic number.

1221539 is a deficient number, since it is larger than the sum of its proper divisors (111061).

1221539 is a wasteful number, since it uses less digits than its factorization.

1221539 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 111060.

The product of its digits is 540, while the sum is 23.

The square root of 1221539 is about 1105.2325547142. The cubic root of 1221539 is about 106.8978849344.

It can be divided in two parts, 122 and 1539, that added together give a palindrome (1661).

The spelling of 1221539 in words is "one million, two hundred twenty-one thousand, five hundred thirty-nine".