1221804828 has 36 divisors (see below), whose sum is σ = 3092052600. Its totient is φ = 406793376.

The previous prime is 1221804791. The next prime is 1221804839. The reversal of 1221804828 is 8284081221.

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 1221804792 and 1221804801.

It is a congruent number.

It is an unprimeable number.

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, 12223 + ... + 50921.

It is an arithmetic number, because the mean of its divisors is an integer number (85890350).

Almost surely, 2^1221804828 is an apocalyptic number.

1221804828 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

1221804828 is an abundant number, since it is smaller than the sum of its proper divisors (1870247772).

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

1221804828 is a wasteful number, since it uses less digits than its factorization.

1221804828 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39586 (or 39581 counting only the distinct ones).

The product of its (nonzero) digits is 16384, while the sum is 36.

The square root of 1221804828 is about 34954.3248826236. The cubic root of 1221804828 is about 1069.0563864778.

The spelling of 1221804828 in words is "one billion, two hundred twenty-one million, eight hundred four thousand, eight hundred twenty-eight".