7561216321 has 16 divisors (see below), whose sum is σ = 7855165440. Its totient is φ = 7273665360.

The previous prime is 7561216319. The next prime is 7561216337. The reversal of 7561216321 is 1236121657.

It is a cyclic number.

It is not a de Polignac number, because 7561216321 - 2¹ = 7561216319 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (7561211321) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 838366 + ... + 847336.

It is an arithmetic number, because the mean of its divisors is an integer number (490947840).

Almost surely, 2^7561216321 is an apocalyptic number.

It is an amenable number.

7561216321 is a deficient number, since it is larger than the sum of its proper divisors (293949119).

7561216321 is a wasteful number, since it uses less digits than its factorization.

7561216321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9324.

The product of its digits is 15120, while the sum is 34.

The square root of 7561216321 is about 86955.2547060843. The cubic root of 7561216321 is about 1962.7450362002.

Adding to 7561216321 its reverse (1236121657), we get a palindrome (8797337978).

The spelling of 7561216321 in words is "seven billion, five hundred sixty-one million, two hundred sixteen thousand, three hundred twenty-one".