65644369920 has 1152 divisors, whose sum is σ = 261006520320. Its totient is φ = 15765995520.

The previous prime is 65644369919. The next prime is 65644369939. The reversal of 65644369920 is 2996344656.

65644369920 is a `hidden beast` number, since 6 + 56 + 443 + 69 + 92 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (1152).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 1774172142 + ... + 1774172178.

It is an arithmetic number, because the mean of its divisors is an integer number (226568160).

Almost surely, 2^65644369920 is an apocalyptic number.

65644369920 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 65644369920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (130503260160).

65644369920 is an abundant number, since it is smaller than the sum of its proper divisors (195362150400).

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

65644369920 is a wasteful number, since it uses less digits than its factorization.

65644369920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 133 (or 101 counting only the distinct ones).

The product of its (nonzero) digits is 8398080, while the sum is 54.

The spelling of 65644369920 in words is "sixty-five billion, six hundred forty-four million, three hundred sixty-nine thousand, nine hundred twenty".