65643516400 has 540 divisors, whose sum is σ = 204572375280. Its totient is φ = 20165376000.

The previous prime is 65643516361. The next prime is 65643516409. The reversal of 65643516400 is 461534656.

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65643516409) by changing a digit.

It is a polite number, since it can be written in 107 ways as a sum of consecutive naturals, for example, 211072245 + ... + 211072555.

It is an arithmetic number, because the mean of its divisors is an integer number (378837732).

Almost surely, 2^65643516400 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 65643516400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (102286187640).

65643516400 is an abundant number, since it is smaller than the sum of its proper divisors (138928858880).

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

65643516400 is a wasteful number, since it uses less digits than its factorization.

65643516400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 454 (or 425 counting only the distinct ones).

The product of its (nonzero) digits is 259200, while the sum is 40.

The spelling of 65643516400 in words is "sixty-five billion, six hundred forty-three million, five hundred sixteen thousand, four hundred".