65640061 has 4 divisors (see below), whose sum is σ = 65922012. Its totient is φ = 65358112.

The previous prime is 65640049. The next prime is 65640083. The reversal of 65640061 is 16004656.

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 39312900 + 26327161 = 6270^2 + 5131^2 .

It is a cyclic number.

It is not a de Polignac number, because 65640061 - 2⁷ = 65639933 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65640461) 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, 140626 + ... + 141091.

It is an arithmetic number, because the mean of its divisors is an integer number (16480503).

Almost surely, 2^65640061 is an apocalyptic number.

It is an amenable number.

65640061 is a deficient number, since it is larger than the sum of its proper divisors (281951).

65640061 is a wasteful number, since it uses less digits than its factorization.

65640061 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 281950.

The product of its (nonzero) digits is 4320, while the sum is 28.

The square root of 65640061 is about 8101.8554047823. The cubic root of 65640061 is about 403.3880160968.

The spelling of 65640061 in words is "sixty-five million, six hundred forty thousand, sixty-one".