1211553200 has 240 divisors, whose sum is σ = 3487276800. Its totient is φ = 398668800.

The previous prime is 1211553199. The next prime is 1211553223. The reversal of 1211553200 is 23551121.

It is a happy number.

It is a super-2 number, since 2×1211553200² = 2935722312860480000, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 3374621 + ... + 3374979.

It is an arithmetic number, because the mean of its divisors is an integer number (14530320).

Almost surely, 2^1211553200 is an apocalyptic number.

1211553200 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 1211553200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1743638400).

1211553200 is an abundant number, since it is smaller than the sum of its proper divisors (2275723600).

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

1211553200 is a wasteful number, since it uses less digits than its factorization.

1211553200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 460 (or 449 counting only the distinct ones).

The product of its (nonzero) digits is 300, while the sum is 20.

The square root of 1211553200 is about 34807.3727822138. The cubic root of 1211553200 is about 1066.0579904083.

The spelling of 1211553200 in words is "one billion, two hundred eleven million, five hundred fifty-three thousand, two hundred".