661459680 has 288 divisors, whose sum is σ = 2600252928. Its totient is φ = 149990400.

The previous prime is 661459639. The next prime is 661459697. The reversal of 661459680 is 86954166.

661459680 is digitally balanced in base 6, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (288).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 2126725 + ... + 2127035.

It is an arithmetic number, because the mean of its divisors is an integer number (9028656).

Almost surely, 2^661459680 is an apocalyptic number.

661459680 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 661459680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1300126464).

661459680 is an abundant number, since it is smaller than the sum of its proper divisors (1938793248).

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

661459680 is a wasteful number, since it uses less digits than its factorization.

661459680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 550 (or 539 counting only the distinct ones).

The product of its (nonzero) digits is 311040, while the sum is 45.

The square root of 661459680 is about 25718.8584505611. The cubic root of 661459680 is about 871.3001567088.

The spelling of 661459680 in words is "six hundred sixty-one million, four hundred fifty-nine thousand, six hundred eighty".