65138831520 has 384 divisors, whose sum is σ = 243223658496. Its totient is φ = 14343008256.

The previous prime is 65138831491. The next prime is 65138831533. The reversal of 65138831520 is 2513883156.

It is a Harshad number since it is a multiple of its sum of digits (42).

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, 12802417 + ... + 12807503.

It is an arithmetic number, because the mean of its divisors is an integer number (633394944).

Almost surely, 2^65138831520 is an apocalyptic number.

65138831520 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 65138831520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (121611829248).

65138831520 is an abundant number, since it is smaller than the sum of its proper divisors (178084826976).

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

65138831520 is a wasteful number, since it uses less digits than its factorization.

65138831520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5252 (or 5244 counting only the distinct ones).

The product of its (nonzero) digits is 172800, while the sum is 42.

The spelling of 65138831520 in words is "sixty-five billion, one hundred thirty-eight million, eight hundred thirty-one thousand, five hundred twenty".