661772760 has 64 divisors (see below), whose sum is σ = 2165806080. Its totient is φ = 160429440.

The previous prime is 661772747. The next prime is 661772791. The reversal of 661772760 is 67277166.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 249352 + ... + 251991.

It is an arithmetic number, because the mean of its divisors is an integer number (33840720).

Almost surely, 2^661772760 is an apocalyptic number.

661772760 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

661772760 is an abundant number, since it is smaller than the sum of its proper divisors (1504033320).

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

661772760 is a wasteful number, since it uses less digits than its factorization.

661772760 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 501368 (or 501364 counting only the distinct ones).

The product of its (nonzero) digits is 148176, while the sum is 42.

The square root of 661772760 is about 25724.9443148085. The cubic root of 661772760 is about 871.4376020359.

The spelling of 661772760 in words is "six hundred sixty-one million, seven hundred seventy-two thousand, seven hundred sixty".