73664640 has 480 divisors, whose sum is σ = 316572300. Its totient is φ = 16257024.

The previous prime is 73664629. The next prime is 73664641. The reversal of 73664640 is 4646637.

73664640 is a `hidden beast` number, since 7 + 3 + 6 + 6 + 4 + 640 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 73410624 + 254016 = 8568^2 + 504^2 .

It is a tau number, because it is divible by the number of its divisors (480).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 73664595 and 73664604.

It is not an unprimeable number, because it can be changed into a prime (73664641) by changing a digit.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 2540146 + ... + 2540174.

Almost surely, 2^73664640 is an apocalyptic number.

73664640 is a gapful number since it is divisible by the number (70) 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 73664640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (158286150).

73664640 is an abundant number, since it is smaller than the sum of its proper divisors (242907660).

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

73664640 is a wasteful number, since it uses less digits than its factorization.

73664640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 74 (or 46 counting only the distinct ones).

The product of its (nonzero) digits is 72576, while the sum is 36.

The square root of 73664640 is about 8582.8107284269. The cubic root of 73664640 is about 419.1984713345.

The spelling of 73664640 in words is "seventy-three million, six hundred sixty-four thousand, six hundred forty".