661680000 has 240 divisors, whose sum is σ = 2381893800. Its totient is φ = 176256000.

The previous prime is 661679983. The next prime is 661680029. The reversal of 661680000 is 86166.

It is a tau number, because it is divible by the number of its divisors (240).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 29 ways as a sum of consecutive naturals, for example, 719541 + ... + 720459.

Almost surely, 2^661680000 is an apocalyptic number.

661680000 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 661680000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1190946900).

661680000 is an abundant number, since it is smaller than the sum of its proper divisors (1720213800).

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

661680000 is an equidigital number, since it uses as much as digits as its factorization.

661680000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 959 (or 929 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The square root of 661680000 is about 25723.1413322712. The cubic root of 661680000 is about 871.3968839657.

The spelling of 661680000 in words is "six hundred sixty-one million, six hundred eighty thousand".