1221604 has 6 divisors (see below), whose sum is σ = 2137814. Its totient is φ = 610800.

The previous prime is 1221601. The next prime is 1221631. The reversal of 1221604 is 4061221.

It can be written as a sum of positive squares in only one way, i.e., 656100 + 565504 = 810^2 + 752^2 .

It is not an unprimeable number, because it can be changed into a prime (1221601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 152697 + ... + 152704.

2^1221604 is an apocalyptic number.

It is an amenable number.

1221604 is a deficient number, since it is larger than the sum of its proper divisors (916210).

1221604 is a wasteful number, since it uses less digits than its factorization.

1221604 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 305405 (or 305403 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 16.

The square root of 1221604 is about 1105.2619598991. The cubic root of 1221604 is about 106.8997809686.

Adding to 1221604 its reverse (4061221), we get a palindrome (5282825).

The spelling of 1221604 in words is "one million, two hundred twenty-one thousand, six hundred four".