1220145 has 8 divisors (see below), whose sum is σ = 1952256. Its totient is φ = 650736.

The previous prime is 1220099. The next prime is 1220147. The reversal of 1220145 is 5410221.

1220145 = 69² + 70² + ... + 158².

It is a sphenic number, since it is the product of 3 distinct primes.

It is a de Polignac number, because none of the positive numbers 2^k-1220145 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (15), and also a Moran number because the ratio is a prime number: 81343 = 1220145 / (1 + 2 + 2 + 0 + 1 + 4 + 5).

1220145 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (1220147) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 40657 + ... + 40686.

It is an arithmetic number, because the mean of its divisors is an integer number (244032).

2^1220145 is an apocalyptic number.

1220145 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1220145 is a deficient number, since it is larger than the sum of its proper divisors (732111).

1220145 is an equidigital number, since it uses as much as digits as its factorization.

1220145 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 81351.

The product of its (nonzero) digits is 80, while the sum is 15.

The square root of 1220145 is about 1104.6017381844. The cubic root of 1220145 is about 106.8572060934.

Adding to 1220145 its reverse (5410221), we get a palindrome (6630366).

It can be divided in two parts, 12201 and 45, that added together give a triangular number (12246 = T₁₅₆).

The spelling of 1220145 in words is "one million, two hundred twenty thousand, one hundred forty-five".