1221001200 has 360 divisors, whose sum is σ = 4565841696. Its totient is φ = 301056000.

The previous prime is 1221001189. The next prime is 1221001261. The reversal of 1221001200 is 21001221.

It is a tau number, because it is divible by the number of its divisors (360).

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 4345060 + ... + 4345340.

Almost surely, 2^1221001200 is an apocalyptic number.

1221001200 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 1221001200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2282920848).

1221001200 is an abundant number, since it is smaller than the sum of its proper divisors (3344840496).

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

1221001200 is a wasteful number, since it uses less digits than its factorization.

1221001200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 393 (or 379 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

The square root of 1221001200 is about 34942.8275902223. The cubic root of 1221001200 is about 1068.8219485779.

Adding to 1221001200 its reverse (21001221), we get a palindrome (1242002421).

The spelling of 1221001200 in words is "one billion, two hundred twenty-one million, one thousand, two hundred".