65665840 has 40 divisors (see below), whose sum is σ = 153302688. Its totient is φ = 26158080.

The previous prime is 65665837. The next prime is 65665871. The reversal of 65665840 is 4856656.

It is a tau number, because it is divible by the number of its divisors (40).

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a junction number, because it is equal to n+sod(n) for n = 65665793 and 65665802.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19480 + ... + 22600.

Almost surely, 2^65665840 is an apocalyptic number.

It is an amenable number.

65665840 is an abundant number, since it is smaller than the sum of its proper divisors (87636848).

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

65665840 is a wasteful number, since it uses less digits than its factorization.

65665840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3397 (or 3391 counting only the distinct ones).

The product of its (nonzero) digits is 172800, while the sum is 40.

The square root of 65665840 is about 8103.4461804840. The cubic root of 65665840 is about 403.4408170767.

The spelling of 65665840 in words is "sixty-five million, six hundred sixty-five thousand, eight hundred forty".