64334640 has 80 divisors (see below), whose sum is σ = 200674656. Its totient is φ = 17049600.

The previous prime is 64334639. The next prime is 64334651. The reversal of 64334640 is 4643346.

It is a tau number, because it is divible by the number of its divisors (80).

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

It is a junction number, because it is equal to n+sod(n) for n = 64334598 and 64334607.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 42700 + ... + 44180.

Almost surely, 2^64334640 is an apocalyptic number.

64334640 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 64334640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (100337328).

64334640 is an abundant number, since it is smaller than the sum of its proper divisors (136340016).

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

64334640 is a wasteful number, since it uses less digits than its factorization.

64334640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1678 (or 1672 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 30.

The square root of 64334640 is about 8020.8877314173. The cubic root of 64334640 is about 400.6959550807.

Adding to 64334640 its reverse (4643346), we get a palindrome (68977986).

The spelling of 64334640 in words is "sixty-four million, three hundred thirty-four thousand, six hundred forty".