661937760 has 432 divisors, whose sum is σ = 2588105520. Its totient is φ = 153753600.

The previous prime is 661937753. The next prime is 661937777. The reversal of 661937760 is 67739166.

661937760 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×661937760² = 876323196227635200, which contains 22 as substring.

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 71 ways as a sum of consecutive naturals, for example, 5052895 + ... + 5053025.

It is an arithmetic number, because the mean of its divisors is an integer number (5990985).

Almost surely, 2^661937760 is an apocalyptic number.

661937760 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 661937760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1294052760).

661937760 is an abundant number, since it is smaller than the sum of its proper divisors (1926167760).

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

661937760 is a wasteful number, since it uses less digits than its factorization.

661937760 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 203 (or 181 counting only the distinct ones).

The product of its (nonzero) digits is 285768, while the sum is 45.

The square root of 661937760 is about 25728.1511189592. The cubic root of 661937760 is about 871.5100212834.

The spelling of 661937760 in words is "six hundred sixty-one million, nine hundred thirty-seven thousand, seven hundred sixty".