65312561 has 4 divisors (see below), whose sum is σ = 66046500. Its totient is φ = 64578624.

The previous prime is 65312543. The next prime is 65312573. The reversal of 65312561 is 16521356.

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

It can be written as a sum of positive squares in 2 ways, for example, as 13184161 + 52128400 = 3631^2 + 7220^2 .

It is a cyclic number.

It is not a de Polignac number, because 65312561 - 2⁶ = 65312497 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (65312581) 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, 366836 + ... + 367013.

It is an arithmetic number, because the mean of its divisors is an integer number (16511625).

Almost surely, 2^65312561 is an apocalyptic number.

It is an amenable number.

65312561 is a deficient number, since it is larger than the sum of its proper divisors (733939).

65312561 is an equidigital number, since it uses as much as digits as its factorization.

65312561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 733938.

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

The square root of 65312561 is about 8081.6187116196. The cubic root of 65312561 is about 402.7160184523.

The spelling of 65312561 in words is "sixty-five million, three hundred twelve thousand, five hundred sixty-one".