64545440 has 48 divisors (see below), whose sum is σ = 153929160. Its totient is φ = 25574400.

The previous prime is 64545433. The next prime is 64545443. The reversal of 64545440 is 4454546.

It can be written as a sum of positive squares in 4 ways, for example, as 54228496 + 10316944 = 7364^2 + 3212^2 .

It is a super-2 number, since 2×64545440² = 8332227649587200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (32).

It is a junction number, because it is equal to n+sod(n) for n = 64545397 and 64545406.

It is not an unprimeable number, because it can be changed into a prime (64545443) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15590 + ... + 19290.

Almost surely, 2^64545440 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 64545440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (76964580).

64545440 is an abundant number, since it is smaller than the sum of its proper divisors (89383720).

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

64545440 is a wasteful number, since it uses less digits than its factorization.

64545440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3825 (or 3817 counting only the distinct ones).

The product of its (nonzero) digits is 38400, while the sum is 32.

The square root of 64545440 is about 8034.0176748623. The cubic root of 64545440 is about 401.1331203977.

Adding to 64545440 its reverse (4454546), we get a palindrome (68999986).

The spelling of 64545440 in words is "sixty-four million, five hundred forty-five thousand, four hundred forty".