65613240 has 320 divisors, whose sum is σ = 275996160. Its totient is φ = 13582080.

The previous prime is 65613239. The next prime is 65613241. The reversal of 65613240 is 4231656.

65613240 is a `hidden beast` number, since 6 + 5 + 613 + 2 + 40 = 666.

It is an interprime number because it is at equal distance from previous prime (65613239) and next prime (65613241).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65613241) by changing a digit.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 249349 + ... + 249611.

It is an arithmetic number, because the mean of its divisors is an integer number (862488).

Almost surely, 2^65613240 is an apocalyptic number.

65613240 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 65613240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (137998080).

65613240 is an abundant number, since it is smaller than the sum of its proper divisors (210382920).

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

65613240 is a wasteful number, since it uses less digits than its factorization.

65613240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 304 (or 291 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 27.

The square root of 65613240 is about 8100.1999975309. The cubic root of 65613240 is about 403.3330661990. Note that the first 3 decimals are identical.

Adding to 65613240 its reverse (4231656), we get a palindrome (69844896).

It can be divided in two parts, 6561 and 3240, that added together give a square (9801 = 99²).

The spelling of 65613240 in words is "sixty-five million, six hundred thirteen thousand, two hundred forty".