1616331521 has 4 divisors (see below), whose sum is σ = 1847236032. Its totient is φ = 1385427012.

The previous prime is 1616331511. The next prime is 1616331523. The reversal of 1616331521 is 1251336161.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1616331521 - 2²⁶ = 1549222657 is a prime.

It is a super-2 number, since 2×1616331521² = 5225055171556346882, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1616331523) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 115452245 + ... + 115452258.

It is an arithmetic number, because the mean of its divisors is an integer number (461809008).

Almost surely, 2^1616331521 is an apocalyptic number.

It is an amenable number.

1616331521 is a deficient number, since it is larger than the sum of its proper divisors (230904511).

1616331521 is an equidigital number, since it uses as much as digits as its factorization.

1616331521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 230904510.

The product of its digits is 3240, while the sum is 29.

The square root of 1616331521 is about 40203.6257195791. The cubic root of 1616331521 is about 1173.5731032163.

Adding to 1616331521 its reverse (1251336161), we get a palindrome (2867667682).

The spelling of 1616331521 in words is "one billion, six hundred sixteen million, three hundred thirty-one thousand, five hundred twenty-one".