65440040 has 16 divisors (see below), whose sum is σ = 147240180. Its totient is φ = 26176000.

The previous prime is 65440033. The next prime is 65440049. The reversal of 65440040 is 4004456.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 65383396 + 56644 = 8086^2 + 238^2 .

It is a junction number, because it is equal to n+sod(n) for n = 65439988 and 65440015.

It is not an unprimeable number, because it can be changed into a prime (65440049) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 817961 + ... + 818040.

Almost surely, 2^65440040 is an apocalyptic number.

It is an amenable number.

65440040 is an abundant number, since it is smaller than the sum of its proper divisors (81800140).

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

65440040 is a wasteful number, since it uses less digits than its factorization.

65440040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1636012 (or 1636008 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 23.

The square root of 65440040 is about 8089.5018388032. The cubic root of 65440040 is about 402.9778592060.

Adding to 65440040 its reverse (4004456), we get a palindrome (69444496).

The spelling of 65440040 in words is "sixty-five million, four hundred forty thousand, forty".