7321561 has 4 divisors (see below), whose sum is σ = 7884772. Its totient is φ = 6758352.

The previous prime is 7321541. The next prime is 7321583. The reversal of 7321561 is 1651237.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1651237 = 7 ⋅235891.

It can be written as a sum of positive squares in 2 ways, for example, as 2673225 + 4648336 = 1635^2 + 2156^2 .

It is a cyclic number.

It is not a de Polignac number, because 7321561 - 2⁵ = 7321529 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 15.

It is not an unprimeable number, because it can be changed into a prime (7321541) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 281586 + ... + 281611.

It is an arithmetic number, because the mean of its divisors is an integer number (1971193).

Almost surely, 2^7321561 is an apocalyptic number.

It is an amenable number.

7321561 is a deficient number, since it is larger than the sum of its proper divisors (563211).

7321561 is a wasteful number, since it uses less digits than its factorization.

7321561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 563210.

The product of its digits is 1260, while the sum is 25.

The square root of 7321561 is about 2705.8383174166. The cubic root of 7321561 is about 194.1785386549.

Adding to 7321561 its reverse (1651237), we get a palindrome (8972798).

The spelling of 7321561 in words is "seven million, three hundred twenty-one thousand, five hundred sixty-one".