661536744 has 64 divisors (see below), whose sum is σ = 1814400000. Its totient is φ = 199331520.

The previous prime is 661536721. The next prime is 661536751. The reversal of 661536744 is 447635166.

It is a junction number, because it is equal to n+sod(n) for n = 661536696 and 661536705.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 40257 + ... + 54255.

It is an arithmetic number, because the mean of its divisors is an integer number (28350000).

Almost surely, 2^661536744 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 661536744, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (907200000).

661536744 is an abundant number, since it is smaller than the sum of its proper divisors (1152863256).

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

661536744 is a wasteful number, since it uses less digits than its factorization.

661536744 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14198 (or 14194 counting only the distinct ones).

The product of its digits is 362880, while the sum is 42.

The square root of 661536744 is about 25720.3566071701. The cubic root of 661536744 is about 871.3339926174. Note that the first 3 decimals are identical.

The spelling of 661536744 in words is "six hundred sixty-one million, five hundred thirty-six thousand, seven hundred forty-four".