64401440 has 48 divisors (see below), whose sum is σ = 161105112. Its totient is φ = 24244224.

The previous prime is 64401427. The next prime is 64401479. The reversal of 64401440 is 4410446.

64401440 = 481² + 482² + ... + 672².

It can be written as a sum of positive squares in 4 ways, for example, as 56130064 + 8271376 = 7492^2 + 2876^2 .

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 9119 + ... + 14558.

Almost surely, 2^64401440 is an apocalyptic number.

It is an amenable number.

64401440 is an abundant number, since it is smaller than the sum of its proper divisors (96703672).

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

64401440 is a wasteful number, since it uses less digits than its factorization.

64401440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23709 (or 23701 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 23.

The square root of 64401440 is about 8025.0507786555. The cubic root of 64401440 is about 400.8345907679.

Adding to 64401440 its reverse (4410446), we get a palindrome (68811886).

The spelling of 64401440 in words is "sixty-four million, four hundred one thousand, four hundred forty".