1551220 has 36 divisors (see below), whose sum is σ = 3586212. Its totient is φ = 563200.

The previous prime is 1551203. The next prime is 1551229. The reversal of 1551220 is 221551.

It can be written as a sum of positive squares in 2 ways, for example, as 1024144 + 527076 = 1012^2 + 726^2 .

It is a junction number, because it is equal to n+sod(n) for n = 1551194 and 1551203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1551229) 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 11 ways as a sum of consecutive naturals, for example, 2100 + ... + 2740.

It is an arithmetic number, because the mean of its divisors is an integer number (99617).

2^1551220 is an apocalyptic number.

1551220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1551220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1793106).

1551220 is an abundant number, since it is smaller than the sum of its proper divisors (2034992).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1551220 is a wasteful number, since it uses less digits than its factorization.

1551220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 672 (or 659 counting only the distinct ones).

The product of its (nonzero) digits is 100, while the sum is 16.

The square root of 1551220 is about 1245.4798272152. The cubic root of 1551220 is about 115.7598081898.

Adding to 1551220 its reverse (221551), we get a palindrome (1772771).

It can be divided in two parts, 1551 and 220, that added together give a palindrome (1771).

The spelling of 1551220 in words is "one million, five hundred fifty-one thousand, two hundred twenty".