1221386400 has 216 divisors, whose sum is σ = 4638570300. Its totient is φ = 300625920.

The previous prime is 1221386389. The next prime is 1221386423. The reversal of 1221386400 is 46831221.

1221386400 is a `hidden beast` number, since 1 + 2 + 2 + 13 + 8 + 640 + 0 = 666.

It can be written as a sum of positive squares in 6 ways, for example, as 263607696 + 957778704 = 16236^2 + 30948^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 87076 + ... + 100124.

Almost surely, 2^1221386400 is an apocalyptic number.

1221386400 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 1221386400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2319285150).

1221386400 is an abundant number, since it is smaller than the sum of its proper divisors (3417183900).

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

1221386400 is a wasteful number, since it uses less digits than its factorization.

1221386400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13088 (or 13072 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 27.

The square root of 1221386400 is about 34948.3390163252. The cubic root of 1221386400 is about 1068.9343336508.

The spelling of 1221386400 in words is "one billion, two hundred twenty-one million, three hundred eighty-six thousand, four hundred".