1821604 has 6 divisors (see below), whose sum is σ = 3187814. Its totient is φ = 910800.

The previous prime is 1821583. The next prime is 1821613. The reversal of 1821604 is 4061281.

It can be written as a sum of positive squares in only one way, i.e., 1102500 + 719104 = 1050^2 + 848^2 .

It is a super-2 number, since 2×1821604² = 6636482265632, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 227697 + ... + 227704.

2^1821604 is an apocalyptic number.

It is an amenable number.

1821604 is a deficient number, since it is larger than the sum of its proper divisors (1366210).

1821604 is a wasteful number, since it uses less digits than its factorization.

1821604 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 455405 (or 455403 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 22.

The square root of 1821604 is about 1349.6681073508. The cubic root of 1821604 is about 122.1287720319.

Adding to 1821604 its reverse (4061281), we get a palindrome (5882885).

The spelling of 1821604 in words is "one million, eight hundred twenty-one thousand, six hundred four".