661090560 has 576 divisors, whose sum is σ = 2596043520. Its totient is φ = 141557760.

The previous prime is 661090513. The next prime is 661090597. The reversal of 661090560 is 65090166.

It is a super-2 number, since 2×661090560² = 874081457042227200, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 16124140 + ... + 16124180.

It is an arithmetic number, because the mean of its divisors is an integer number (4507020).

Almost surely, 2^661090560 is an apocalyptic number.

661090560 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 661090560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1298021760).

661090560 is an abundant number, since it is smaller than the sum of its proper divisors (1934952960).

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

661090560 is a wasteful number, since it uses less digits than its factorization.

661090560 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 114 (or 100 counting only the distinct ones).

The product of its (nonzero) digits is 9720, while the sum is 33.

The square root of 661090560 is about 25711.6813919277. The cubic root of 661090560 is about 871.1380535268.

The spelling of 661090560 in words is "six hundred sixty-one million, ninety thousand, five hundred sixty".