1323155551 has 4 divisors (see below), whose sum is σ = 1323270000. Its totient is φ = 1323041104.

The previous prime is 1323155521. The next prime is 1323155593. The reversal of 1323155551 is 1555513231.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1323155551 is a prime.

It is a super-2 number, since 2×1323155551² = 3501481224284227202, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1323155521) 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, 37651 + ... + 63748.

It is an arithmetic number, because the mean of its divisors is an integer number (330817500).

Almost surely, 2^1323155551 is an apocalyptic number.

1323155551 is a deficient number, since it is larger than the sum of its proper divisors (114449).

1323155551 is a wasteful number, since it uses less digits than its factorization.

1323155551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 114448.

The product of its digits is 11250, while the sum is 31.

The square root of 1323155551 is about 36375.2051678063. The cubic root of 1323155551 is about 1097.8347354072.

Adding to 1323155551 its reverse (1555513231), we get a palindrome (2878668782).

The spelling of 1323155551 in words is "one billion, three hundred twenty-three million, one hundred fifty-five thousand, five hundred fifty-one".