1221599 has 4 divisors (see below), whose sum is σ = 1274736. Its totient is φ = 1168464.

The previous prime is 1221593. The next prime is 1221601. The reversal of 1221599 is 9951221.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9951221 = 7 ⋅1421603.

It is a cyclic number.

It is not a de Polignac number, because 1221599 - 2²⁰ = 173023 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221593) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26534 + ... + 26579.

It is an arithmetic number, because the mean of its divisors is an integer number (318684).

2^1221599 is an apocalyptic number.

1221599 is a deficient number, since it is larger than the sum of its proper divisors (53137).

1221599 is an equidigital number, since it uses as much as digits as its factorization.

1221599 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53136.

The product of its digits is 1620, while the sum is 29.

The square root of 1221599 is about 1105.2596979896. The cubic root of 1221599 is about 106.8996351222.

The spelling of 1221599 in words is "one million, two hundred twenty-one thousand, five hundred ninety-nine".