65321561 has 4 divisors (see below), whose sum is σ = 65836032. Its totient is φ = 64807092.

The previous prime is 65321527. The next prime is 65321567. The reversal of 65321561 is 16512356.

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 a de Polignac number, because none of the positive numbers 2^k-65321561 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (65321567) 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, 257045 + ... + 257298.

It is an arithmetic number, because the mean of its divisors is an integer number (16459008).

Almost surely, 2^65321561 is an apocalyptic number.

It is an amenable number.

65321561 is a deficient number, since it is larger than the sum of its proper divisors (514471).

65321561 is a wasteful number, since it uses less digits than its factorization.

65321561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 514470.

The product of its digits is 5400, while the sum is 29.

The square root of 65321561 is about 8082.1755115810. The cubic root of 65321561 is about 402.7345155461.

The spelling of 65321561 in words is "sixty-five million, three hundred twenty-one thousand, five hundred sixty-one".