65540561520 has 240 divisors, whose sum is σ = 237106351008. Its totient is φ = 14932592640.

The previous prime is 65540561501. The next prime is 65540561539. The reversal of 65540561520 is 2516504556.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (65540561501) and next prime (65540561539).

It is a tau number, because it is divible by the number of its divisors (240).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 3719130 + ... + 3736710.

Almost surely, 2^65540561520 is an apocalyptic number.

65540561520 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 65540561520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (118553175504).

65540561520 is an abundant number, since it is smaller than the sum of its proper divisors (171565789488).

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

65540561520 is a wasteful number, since it uses less digits than its factorization.

65540561520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17928 (or 17915 counting only the distinct ones).

The product of its (nonzero) digits is 180000, while the sum is 39.

The spelling of 65540561520 in words is "sixty-five billion, five hundred forty million, five hundred sixty-one thousand, five hundred twenty".