1213521200 has 120 divisors (see below), whose sum is σ = 3153494592. Its totient is φ = 447016960.

The previous prime is 1213521173. The next prime is 1213521233. The reversal of 1213521200 is 21253121.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (17).

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 23 ways as a sum of consecutive naturals, for example, 317702 + ... + 321498.

Almost surely, 2^1213521200 is an apocalyptic number.

1213521200 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 1213521200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1576747296).

1213521200 is an abundant number, since it is smaller than the sum of its proper divisors (1939973392).

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

1213521200 is a wasteful number, since it uses less digits than its factorization.

1213521200 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3879 (or 3868 counting only the distinct ones).

The product of its (nonzero) digits is 120, while the sum is 17.

The square root of 1213521200 is about 34835.6311841769. The cubic root of 1213521200 is about 1066.6348992275.

Adding to 1213521200 its reverse (21253121), we get a palindrome (1234774321).

The spelling of 1213521200 in words is "one billion, two hundred thirteen million, five hundred twenty-one thousand, two hundred".