661516064 has 96 divisors (see below), whose sum is σ = 1499057280. Its totient is φ = 284416000.

The previous prime is 661516061. The next prime is 661516067. The reversal of 661516064 is 460615166.

It is an interprime number because it is at equal distance from previous prime (661516061) and next prime (661516067).

It is not an unprimeable number, because it can be changed into a prime (661516061) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 817292 + ... + 818100.

It is an arithmetic number, because the mean of its divisors is an integer number (15615180).

Almost surely, 2^661516064 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 661516064, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (749528640).

661516064 is an abundant number, since it is smaller than the sum of its proper divisors (837541216).

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

661516064 is a wasteful number, since it uses less digits than its factorization.

661516064 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 954 (or 946 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 35.

The square root of 661516064 is about 25719.9545878293. The cubic root of 661516064 is about 871.3249130639.

The spelling of 661516064 in words is "six hundred sixty-one million, five hundred sixteen thousand, sixty-four".