1220399 has 4 divisors (see below), whose sum is σ = 1224264. Its totient is φ = 1216536.

The previous prime is 1220393. The next prime is 1220411. The reversal of 1220399 is 9930221.

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 1220399 - 2¹⁶ = 1154863 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 (1220393) 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, 1412 + ... + 2105.

It is an arithmetic number, because the mean of its divisors is an integer number (306066).

2^1220399 is an apocalyptic number.

1220399 is a deficient number, since it is larger than the sum of its proper divisors (3865).

1220399 is an equidigital number, since it uses as much as digits as its factorization.

1220399 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3864.

The product of its (nonzero) digits is 972, while the sum is 26.

The square root of 1220399 is about 1104.7167057667. The cubic root of 1220399 is about 106.8646204710.

The spelling of 1220399 in words is "one million, two hundred twenty thousand, three hundred ninety-nine".