65128440 has 128 divisors (see below), whose sum is σ = 213373440. Its totient is φ = 15806976.

The previous prime is 65128423. The next prime is 65128457. The reversal of 65128440 is 4482156.

It is an interprime number because it is at equal distance from previous prime (65128423) and next prime (65128457).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a zygodrome in base 2.

It is a junction number, because it is equal to n+sod(n) for n = 65128398 and 65128407.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 129229 + ... + 129731.

It is an arithmetic number, because the mean of its divisors is an integer number (1666980).

Almost surely, 2^65128440 is an apocalyptic number.

65128440 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 65128440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (106686720).

65128440 is an abundant number, since it is smaller than the sum of its proper divisors (148245000).

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

65128440 is a wasteful number, since it uses less digits than its factorization.

65128440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 613 (or 609 counting only the distinct ones).

The product of its (nonzero) digits is 7680, while the sum is 30.

The square root of 65128440 is about 8070.2193278746. The cubic root of 65128440 is about 402.3372334176.

The spelling of 65128440 in words is "sixty-five million, one hundred twenty-eight thousand, four hundred forty".