1211222400 has 192 divisors, whose sum is σ = 4012578000. Its totient is φ = 321126400.

The previous prime is 1211222377. The next prime is 1211222429. The reversal of 1211222400 is 42221121.

It is a tau number, because it is divible by the number of its divisors (192).

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 1211222400.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2697376 + ... + 2697824.

Almost surely, 2^1211222400 is an apocalyptic number.

1211222400 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 1211222400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2006289000).

1211222400 is an abundant number, since it is smaller than the sum of its proper divisors (2801355600).

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

1211222400 is a wasteful number, since it uses less digits than its factorization.

1211222400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 757 (or 740 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 15.

The square root of 1211222400 is about 34802.6205909842. The cubic root of 1211222400 is about 1065.9609568143.

Adding to 1211222400 its reverse (42221121), we get a palindrome (1253443521).

The spelling of 1211222400 in words is "one billion, two hundred eleven million, two hundred twenty-two thousand, four hundred".