65521945 has 4 divisors (see below), whose sum is σ = 78626340. Its totient is φ = 52417552.

The previous prime is 65521921. The next prime is 65521999. The reversal of 65521945 is 54912556.

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 17372224 + 48149721 = 4168^2 + 6939^2 .

It is a cyclic number.

It is not a de Polignac number, because 65521945 - 2²³ = 57133337 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6552190 + ... + 6552199.

It is an arithmetic number, because the mean of its divisors is an integer number (19656585).

Almost surely, 2^65521945 is an apocalyptic number.

It is an amenable number.

65521945 is a deficient number, since it is larger than the sum of its proper divisors (13104395).

65521945 is a wasteful number, since it uses less digits than its factorization.

65521945 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13104394.

The product of its digits is 54000, while the sum is 37.

The square root of 65521945 is about 8094.5626812077. The cubic root of 65521945 is about 403.1459119813.

It can be divided in two parts, 65521 and 945, that added together give a palindrome (66466).

The spelling of 65521945 in words is "sixty-five million, five hundred twenty-one thousand, nine hundred forty-five".