661812256 has 48 divisors (see below), whose sum is σ = 1567460160. Its totient is φ = 268704000.

The previous prime is 661812209. The next prime is 661812259. The reversal of 661812256 is 652218166.

It is not an unprimeable number, because it can be changed into a prime (661812259) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 73495 + ... + 82006.

It is an arithmetic number, because the mean of its divisors is an integer number (32655420).

Almost surely, 2^661812256 is an apocalyptic number.

It is an amenable number.

661812256 is an abundant number, since it is smaller than the sum of its proper divisors (905647904).

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

661812256 is a wasteful number, since it uses less digits than its factorization.

661812256 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 155537 (or 155529 counting only the distinct ones).

The product of its digits is 34560, while the sum is 37.

The square root of 661812256 is about 25725.7119629370. The cubic root of 661812256 is about 871.4549381050.

The spelling of 661812256 in words is "six hundred sixty-one million, eight hundred twelve thousand, two hundred fifty-six".