1320551 has 4 divisors (see below), whose sum is σ = 1325352. Its totient is φ = 1315752.

The previous prime is 1320541. The next prime is 1320607. The reversal of 1320551 is 1550231.

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 1320551 - 2¹⁴ = 1304167 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 (1320541) 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, 1961 + ... + 2546.

It is an arithmetic number, because the mean of its divisors is an integer number (331338).

2^1320551 is an apocalyptic number.

1320551 is a deficient number, since it is larger than the sum of its proper divisors (4801).

1320551 is an equidigital number, since it uses as much as digits as its factorization.

1320551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4800.

The product of its (nonzero) digits is 150, while the sum is 17.

The square root of 1320551 is about 1149.1522962602. The cubic root of 1320551 is about 109.7113922002.

Adding to 1320551 its reverse (1550231), we get a palindrome (2870782).

The spelling of 1320551 in words is "one million, three hundred twenty thousand, five hundred fifty-one".