64815640 has 16 divisors (see below), whose sum is σ = 145835280. Its totient is φ = 25926240.

The previous prime is 64815617. The next prime is 64815643. The reversal of 64815640 is 4651846.

It is a junction number, because it is equal to n+sod(n) for n = 64815596 and 64815605.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64815643) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 810156 + ... + 810235.

It is an arithmetic number, because the mean of its divisors is an integer number (9114705).

Almost surely, 2^64815640 is an apocalyptic number.

It is an amenable number.

64815640 is an abundant number, since it is smaller than the sum of its proper divisors (81019640).

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

64815640 is a wasteful number, since it uses less digits than its factorization.

64815640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1620402 (or 1620398 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 34.

The square root of 64815640 is about 8050.8161076999. The cubic root of 64815640 is about 401.6920820528.

It can be divided in two parts, 6481 and 5640, that added together give a palindrome (12121).

The spelling of 64815640 in words is "sixty-four million, eight hundred fifteen thousand, six hundred forty".