1225620 has 72 divisors (see below), whose sum is σ = 4062240. Its totient is φ = 296640.

The previous prime is 1225603. The next prime is 1225621. The reversal of 1225620 is 265221.

Added to its reverse (265221) it gives a square (1490841 = 1221²).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 1225593 and 1225602.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1225621) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1671 + ... + 2289.

It is an arithmetic number, because the mean of its divisors is an integer number (56420).

2^1225620 is an apocalyptic number.

1225620 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 1225620, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2031120).

1225620 is an abundant number, since it is smaller than the sum of its proper divisors (2836620).

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

1225620 is a wasteful number, since it uses less digits than its factorization.

1225620 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 645 (or 640 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 1225620 is about 1107.0772330782. The cubic root of 1225620 is about 107.0167965014.

Adding to 1225620 its reverse (265221), we get a square (1490841 = 1221²).

The spelling of 1225620 in words is "one million, two hundred twenty-five thousand, six hundred twenty".