65640321 has 16 divisors (see below), whose sum is σ = 101473920. Its totient is φ = 41857200.

The previous prime is 65640319. The next prime is 65640343. The reversal of 65640321 is 12304656.

65640321 is a `hidden beast` number, since 656 + 4 + 0 + 3 + 2 + 1 = 666.

It is not a de Polignac number, because 65640321 - 2¹ = 65640319 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (65640521) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 52230 + ... + 53471.

It is an arithmetic number, because the mean of its divisors is an integer number (6342120).

Almost surely, 2^65640321 is an apocalyptic number.

It is an amenable number.

65640321 is a deficient number, since it is larger than the sum of its proper divisors (35833599).

65640321 is a wasteful number, since it uses less digits than its factorization.

65640321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 105733 (or 105727 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 27.

The square root of 65640321 is about 8101.8714504736. The cubic root of 65640321 is about 403.3885487021.

Adding to 65640321 its reverse (12304656), we get a palindrome (77944977).

The spelling of 65640321 in words is "sixty-five million, six hundred forty thousand, three hundred twenty-one".