65531640 has 32 divisors (see below), whose sum is σ = 196595280. Its totient is φ = 17475072.

The previous prime is 65531633. The next prime is 65531681. The reversal of 65531640 is 4613556.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 65531598 and 65531607.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 272929 + ... + 273168.

Almost surely, 2^65531640 is an apocalyptic number.

65531640 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

65531640 is an abundant number, since it is smaller than the sum of its proper divisors (131063640).

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

65531640 is a wasteful number, since it uses less digits than its factorization.

65531640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 546111 (or 546107 counting only the distinct ones).

The product of its (nonzero) digits is 10800, while the sum is 30.

The square root of 65531640 is about 8095.1615178451. The cubic root of 65531640 is about 403.1657949221.

The spelling of 65531640 in words is "sixty-five million, five hundred thirty-one thousand, six hundred forty".