65640438 has 24 divisors (see below), whose sum is σ = 142567776. Its totient is φ = 21826800.

The previous prime is 65640431. The next prime is 65640461. The reversal of 65640438 is 83404656.

65640438 is a `hidden beast` number, since 6 + 5 + 640 + 4 + 3 + 8 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65640431) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3528 + ... + 11988.

It is an arithmetic number, because the mean of its divisors is an integer number (5940324).

Almost surely, 2^65640438 is an apocalyptic number.

65640438 is an abundant number, since it is smaller than the sum of its proper divisors (76927338).

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

65640438 is a wasteful number, since it uses less digits than its factorization.

65640438 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8900 (or 8897 counting only the distinct ones).

The product of its (nonzero) digits is 69120, while the sum is 36.

The square root of 65640438 is about 8101.8786710244. The cubic root of 65640438 is about 403.3887883741.

The spelling of 65640438 in words is "sixty-five million, six hundred forty thousand, four hundred thirty-eight".