64431540 has 72 divisors (see below), whose sum is σ = 198787680. Its totient is φ = 16887744.

The previous prime is 64431539. The next prime is 64431551. The reversal of 64431540 is 4513446.

64431540 is a `hidden beast` number, since 644 + 3 + 15 + 4 + 0 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 7587 + ... + 13653.

It is an arithmetic number, because the mean of its divisors is an integer number (2760940).

Almost surely, 2^64431540 is an apocalyptic number.

64431540 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 64431540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (99393840).

64431540 is an abundant number, since it is smaller than the sum of its proper divisors (134356140).

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

64431540 is a wasteful number, since it uses less digits than its factorization.

64431540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6141 (or 6136 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 27.

The square root of 64431540 is about 8026.9259371194. The cubic root of 64431540 is about 400.8970285125.

Adding to 64431540 its reverse (4513446), we get a palindrome (68944986).

The spelling of 64431540 in words is "sixty-four million, four hundred thirty-one thousand, five hundred forty".