64263640 has 64 divisors (see below), whose sum is σ = 166037760. Its totient is φ = 21928320.

The previous prime is 64263611. The next prime is 64263659. The reversal of 64263640 is 4636246.

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, 78835 + ... + 79645.

It is an arithmetic number, because the mean of its divisors is an integer number (2594340).

Almost surely, 2^64263640 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 64263640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (83018880).

64263640 is an abundant number, since it is smaller than the sum of its proper divisors (101774120).

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

64263640 is a wasteful number, since it uses less digits than its factorization.

64263640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1112 (or 1108 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 31.

The square root of 64263640 is about 8016.4605656112. The cubic root of 64263640 is about 400.5484975324.

Adding to 64263640 its reverse (4636246), we get a palindrome (68899886).

The spelling of 64263640 in words is "sixty-four million, two hundred sixty-three thousand, six hundred forty".