64509660 has 72 divisors (see below), whose sum is σ = 196363440. Its totient is φ = 17142528.

The previous prime is 64509647. The next prime is 64509661. The reversal of 64509660 is 6690546.

It is a happy number.

64509660 is a `hidden beast` number, since 645 + 0 + 9 + 6 + 6 + 0 = 666.

It is a super-2 number, since 2×64509660² = 8322992466631200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64509661) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 79336 + ... + 80144.

It is an arithmetic number, because the mean of its divisors is an integer number (2727270).

Almost surely, 2^64509660 is an apocalyptic number.

64509660 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 64509660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (98181720).

64509660 is an abundant number, since it is smaller than the sum of its proper divisors (131853780).

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

64509660 is a wasteful number, since it uses less digits than its factorization.

64509660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1267 (or 1262 counting only the distinct ones).

The product of its (nonzero) digits is 38880, while the sum is 36.

The square root of 64509660 is about 8031.7905849194. The cubic root of 64509660 is about 401.0589855664.

It can be divided in two parts, 6450 and 9660, that added together give a triangular number (16110 = T₁₇₉).

The spelling of 64509660 in words is "sixty-four million, five hundred nine thousand, six hundred sixty".