65664540 has 192 divisors, whose sum is σ = 226437120. Its totient is φ = 15713280.

The previous prime is 65664491. The next prime is 65664553. The reversal of 65664540 is 4546656.

It is a happy number.

65664540 is a `hidden beast` number, since 6 + 5 + 6 + 645 + 4 + 0 = 666.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 65664495 and 65664504.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 210985 + ... + 211295.

It is an arithmetic number, because the mean of its divisors is an integer number (1179360).

Almost surely, 2^65664540 is an apocalyptic number.

65664540 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 65664540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (113218560).

65664540 is an abundant number, since it is smaller than the sum of its proper divisors (160772580).

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

65664540 is a wasteful number, since it uses less digits than its factorization.

65664540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 369 (or 361 counting only the distinct ones).

The product of its (nonzero) digits is 86400, while the sum is 36.

The square root of 65664540 is about 8103.3659673003. The cubic root of 65664540 is about 403.4381547258.

The spelling of 65664540 in words is "sixty-five million, six hundred sixty-four thousand, five hundred forty".