661893120 has 624 divisors, whose sum is σ = 2862263040. Its totient is φ = 143327232.

The previous prime is 661893083. The next prime is 661893137. The reversal of 661893120 is 21398166.

661893120 is a `hidden beast` number, since 6 + 618 + 9 + 31 + 2 + 0 = 666.

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

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, 34836471 + ... + 34836489.

It is an arithmetic number, because the mean of its divisors is an integer number (4586960).

Almost surely, 2^661893120 is an apocalyptic number.

661893120 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 661893120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1431131520).

661893120 is an abundant number, since it is smaller than the sum of its proper divisors (2200369920).

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

661893120 is an equidigital number, since it uses as much as digits as its factorization.

661893120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 70 (or 36 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 36.

The square root of 661893120 is about 25727.2835721146. The cubic root of 661893120 is about 871.4904297728.

The spelling of 661893120 in words is "six hundred sixty-one million, eight hundred ninety-three thousand, one hundred twenty".