661757040 has 280 divisors, whose sum is σ = 2637994848. Its totient is φ = 151165440.

The previous prime is 661757021. The next prime is 661757051. The reversal of 661757040 is 40757166.

661757040 is digitally balanced in base 2, 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 (280).

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

It is a junction number, because it is equal to n+sod(n) for n = 661756986 and 661757004.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 55 ways as a sum of consecutive naturals, for example, 407430 + ... + 409050.

Almost surely, 2^661757040 is an apocalyptic number.

661757040 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 661757040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1318997424).

661757040 is an abundant number, since it is smaller than the sum of its proper divisors (1976237808).

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

661757040 is a wasteful number, since it uses less digits than its factorization.

661757040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1659 (or 1638 counting only the distinct ones).

The product of its (nonzero) digits is 35280, while the sum is 36.

The square root of 661757040 is about 25724.6387729741. The cubic root of 661757040 is about 871.4307018287.

The spelling of 661757040 in words is "six hundred sixty-one million, seven hundred fifty-seven thousand, forty".