1321533553 has 8 divisors (see below), whose sum is σ = 1340539200. Its totient is φ = 1302601488.

The previous prime is 1321533547. The next prime is 1321533571. The reversal of 1321533553 is 3553351231.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1321533553 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1321533523) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 18303 + ... + 54571.

It is an arithmetic number, because the mean of its divisors is an integer number (167567400).

Almost surely, 2^1321533553 is an apocalyptic number.

It is an amenable number.

1321533553 is a deficient number, since it is larger than the sum of its proper divisors (19005647).

1321533553 is an equidigital number, since it uses as much as digits as its factorization.

1321533553 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36791.

The product of its digits is 20250, while the sum is 31.

The square root of 1321533553 is about 36352.9029514838. The cubic root of 1321533553 is about 1097.3859562592.

Adding to 1321533553 its reverse (3553351231), we get a palindrome (4874884784).

The spelling of 1321533553 in words is "one billion, three hundred twenty-one million, five hundred thirty-three thousand, five hundred fifty-three".