661747740 has 48 divisors (see below), whose sum is σ = 1865354400. Its totient is φ = 175279360.

The previous prime is 661747721. The next prime is 661747747. The reversal of 661747740 is 47747166.

661747740 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a junction number, because it is equal to n+sod(n) for n = 661747692 and 661747701.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661747747) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 28071 + ... + 45950.

It is an arithmetic number, because the mean of its divisors is an integer number (38861550).

Almost surely, 2^661747740 is an apocalyptic number.

661747740 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

661747740 is an abundant number, since it is smaller than the sum of its proper divisors (1203606660).

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

661747740 is a wasteful number, since it uses less digits than its factorization.

661747740 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 74182 (or 74180 counting only the distinct ones).

The product of its (nonzero) digits is 197568, while the sum is 42.

The square root of 661747740 is about 25724.4580117833. The cubic root of 661747740 is about 871.4266195935.

The spelling of 661747740 in words is "six hundred sixty-one million, seven hundred forty-seven thousand, seven hundred forty".