1243400400 has 360 divisors, whose sum is σ = 4986805824. Its totient is φ = 283545600.

The previous prime is 1243400371. The next prime is 1243400437. The reversal of 1243400400 is 40043421.

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 (18).

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, 672277 + ... + 674123.

Almost surely, 2^1243400400 is an apocalyptic number.

1243400400 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 1243400400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2493402912).

1243400400 is an abundant number, since it is smaller than the sum of its proper divisors (3743405424).

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

1243400400 is a wasteful number, since it uses less digits than its factorization.

1243400400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1899 (or 1885 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 18.

The square root of 1243400400 is about 35261.8831034305. The cubic root of 1243400400 is about 1075.3182111872.

Adding to 1243400400 its reverse (40043421), we get a palindrome (1283443821).

The spelling of 1243400400 in words is "one billion, two hundred forty-three million, four hundred thousand, four hundred".