65643940 has 24 divisors (see below), whose sum is σ = 139221432. Its totient is φ = 25996800.

The previous prime is 65643923. The next prime is 65643943. The reversal of 65643940 is 4934656.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 33085504 + 32558436 = 5752^2 + 5706^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 65643940.

It is not an unprimeable number, because it can be changed into a prime (65643943) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14229 + ... + 18268.

It is an arithmetic number, because the mean of its divisors is an integer number (5800893).

Almost surely, 2^65643940 is an apocalyptic number.

It is an amenable number.

65643940 is an abundant number, since it is smaller than the sum of its proper divisors (73577492).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

65643940 is a wasteful number, since it uses less digits than its factorization.

65643940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32607 (or 32605 counting only the distinct ones).

The product of its (nonzero) digits is 77760, while the sum is 37.

The square root of 65643940 is about 8102.0947908550. The cubic root of 65643940 is about 403.3959620131.

The spelling of 65643940 in words is "sixty-five million, six hundred forty-three thousand, nine hundred forty".