1331665553 has 4 divisors (see below), whose sum is σ = 1334579940. Its totient is φ = 1328751168.

The previous prime is 1331665541. The next prime is 1331665583. The reversal of 1331665553 is 3555661331.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1077677584 + 253987969 = 32828^2 + 15937^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1331665553 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1331665513) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1456508 + ... + 1457421.

It is an arithmetic number, because the mean of its divisors is an integer number (333644985).

Almost surely, 2^1331665553 is an apocalyptic number.

It is an amenable number.

1331665553 is a deficient number, since it is larger than the sum of its proper divisors (2914387).

1331665553 is an equidigital number, since it uses as much as digits as its factorization.

1331665553 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2914386.

The product of its digits is 121500, while the sum is 38.

The square root of 1331665553 is about 36491.9929984647. The cubic root of 1331665553 is about 1100.1833173819.

The spelling of 1331665553 in words is "one billion, three hundred thirty-one million, six hundred sixty-five thousand, five hundred fifty-three".