65515540 has 48 divisors (see below), whose sum is σ = 142425360. Its totient is φ = 25297920.

The previous prime is 65515537. The next prime is 65515543. The reversal of 65515540 is 4551556.

65515540 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (65515537) and next prime (65515543).

It can be written as a sum of positive squares in 8 ways, for example, as 293764 + 65221776 = 542^2 + 8076^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65515543) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 89014 + ... + 89746.

It is an arithmetic number, because the mean of its divisors is an integer number (2967195).

Almost surely, 2^65515540 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 65515540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (71212680).

65515540 is an abundant number, since it is smaller than the sum of its proper divisors (76909820).

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

65515540 is a wasteful number, since it uses less digits than its factorization.

65515540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 892 (or 890 counting only the distinct ones).

The product of its (nonzero) digits is 15000, while the sum is 31.

The square root of 65515540 is about 8094.1670355880. The cubic root of 65515540 is about 403.1327752441.

The spelling of 65515540 in words is "sixty-five million, five hundred fifteen thousand, five hundred forty".