1221648 has 40 divisors (see below), whose sum is σ = 3261696. Its totient is φ = 393600.

The previous prime is 1221641. The next prime is 1221653. The reversal of 1221648 is 8461221.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (1221641) 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, 1078 + ... + 1898.

2^1221648 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1221648, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1630848).

1221648 is an abundant number, since it is smaller than the sum of its proper divisors (2040048).

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

1221648 is a wasteful number, since it uses less digits than its factorization.

1221648 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 863 (or 857 counting only the distinct ones).

The product of its digits is 768, while the sum is 24.

The square root of 1221648 is about 1105.2818645033. The cubic root of 1221648 is about 106.9010643998.

Adding to 1221648 its reverse (8461221), we get a palindrome (9682869).

It can be divided in two parts, 122 and 1648, that added together give a triangular number (1770 = T₅₉).

The spelling of 1221648 in words is "one million, two hundred twenty-one thousand, six hundred forty-eight".