1321538400 has 432 divisors, whose sum is σ = 5738320224. Its totient is φ = 278691840.

The previous prime is 1321538389. The next prime is 1321538429. The reversal of 1321538400 is 48351231.

It is a happy number.

1321538400 is a `hidden beast` number, since 13 + 215 + 38 + 400 = 666.

It is a congruent number.

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 71 ways as a sum of consecutive naturals, for example, 654192 + ... + 656208.

Almost surely, 2^1321538400 is an apocalyptic number.

1321538400 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 1321538400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2869160112).

1321538400 is an abundant number, since it is smaller than the sum of its proper divisors (4416781824).

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

1321538400 is a wasteful number, since it uses less digits than its factorization.

1321538400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2063 (or 2047 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 27.

The square root of 1321538400 is about 36352.9696173504. The cubic root of 1321538400 is about 1097.3872978882.

Adding to 1321538400 its reverse (48351231), we get a palindrome (1369889631).

It can be divided in two parts, 13215 and 38400, that added together give a palindrome (51615).

The spelling of 1321538400 in words is "one billion, three hundred twenty-one million, five hundred thirty-eight thousand, four hundred".